440

NOAA Technical Report NMFS Circular 440

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Marine Flora and Fauna of

the Northeastern United States.

Turbellaria: Acoela and

Nennertodernnatida

Louise F. Bush

July 1981

I

Marine Biological Laboratory

^ LIBRARY

OCT 14 1992

I

Woods Hole, M^ss. |

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atnnospheric Administration

National Marine Fisheries Service
NOAA TECHNICAL REPORTS

National Marine Fisheries Service, Circulars

The major responsibilities ol the National Marine Fisheries Service (NMFS) are to monitor and assess the abundance and geographic distribution of

Tishery resources, to understand and predict fluctuations in the quantity and distribution of these resources, and to establish levels for optimum use of the

resources. NMFS is also charged « ilh the development and implementation of policies for managing national fishing grounds, development and enforce- ment of domestic fisheries regulations, surveillance of foreign fishing off United States coastal waters, and the development and enforcement of international fishery agreements and policies. NMFS also assist-s the fishing industry through marketing service and economic analysis programs, and mortgage

insurance and vessel construction subsidies. It collects, analyzes, and publishes statistics on various phases of the industry. The NOAA Technical Report NMFS Circular series continues a scries |hat has been in existence since 1941 . The Circulars are technical publications of general interest intended to aid conservation and management. Publications that review in considerable detail and at a high technical level certain broad areas of research appear in this series. Technical papers originating in economics studies and from management investigations appear in the Circular

series.NOAA Technical Report NMFS Circulars are available free in limited numbers to governmental agencies, both Federal and State. They are also

available in exchange for other scientific and technical publications in the marine sciences. Individual copies may be obtained (unless otherwise noted) from D822, User Services Branch, Environmental Science Information Center, NOAA, Rockville, MD 20852. Recent Circulars are:

418. Annotated bibliography of four Atlantic scombrids: Scomberomorus .

braslliensis, S. cavalla, S. maculatus, and S. regatis. By Charles S. Manooch III, Eugene L. Nakamura, and Ann Bowman Hall. December 1978, iii-t^ 166 p.

419. Marine flora and fauna of the northeastern United States. Protozoa: Sar- codina: Amoebae. By Eugene C. Bovee and Thomas K. Sawyer. January 1979,

iii + 56 p., 77 figs. For sale by the Superintendent of Documents, U.S. Govern- ment Printing Office. Washington, DC. 20402, Stock No. 003-017-00433-3.

420. Preliminary keys to otoliths of some adull fishes qf the Gulf of Alaska,

Bering Sea, and Beaufort Sea. By James E. Morrow. February 1979, iii + 32 p., 9 pi.

(427.) Coastal upwelling off western North America, 1976. By Craig S. Nelson.

July 1979, p. 65-75, 2 figs., 2 tables.

(427.) Oceanic conditions during 1976 between San Francisco and Honolulu as observed from Ships of Opportunity. By J. F. T. Saur and D. R. McLain. July

1979, p. 77-92, 5 figs., 2 tables.

(427.) The 1976 El Nino and recent progress in monitoring and prediction. By

William H. Quinn. July 1979, p. 93-110. 7 figs., 4 tables.

(427.) Sea surface temperature anomalies. By Douglas R. McLain. July 1979,

p. 111-149. app. I.

421

.

Larval development of shallow water barnacles of the Carolinas (Cirripedia: Thoracica) with keys to naupliar stages. By William H. Lang. February

1979, iv + 39 p., 36 figs., 17 tables.

422. A revision of the caisharks, family Scyliohinidae. By Stewart Springer. April 1979, v+ 142 p., 97 figs. For sale by the Superintendent of Documents.

U.S. Government Printing Office. Washington. D.C. 20402, Slock No.

003-020-00147-5.

423. Marine flora and fauna of the northeastern United States. Crustacea: Cumacea. By Les Watling. April 1979, iii-f23 p., 35 figs. For sale by the Superintendent of Documents. Washington, D.C. 20402, Stock No.

0O3-017-0O446-5.

(427.) Fluctuations of sea surface temperature and density at coastal stations during 1976. By Douglas R. McLain, July 1979, p. 151-166, 7 figs., app. I.

(427.) Data on cold weather conditions along the Atlantic and Gulf coasts during the fall and winter of 1976-77. By J. Lockwood Chamberlin and Reed S. Armstrong. July 1979, p. 167-174, 1 fig., I table.

(427.) Wind driven transport Atlantic coast and Gulf of Mexico. By MertonC.

Ingraham. July 1979, p. 175-208, 4 figs., 1 table, app. 1.

(427.) Sea surface temperature distribution from Cape Cod. Massachusetts, to Miami, Florida - 1976. By Joseph W. Deaver 111. July 1979, p. 209-229, 3 figs., 2

tables, app. I

.

424. Guide to the leptocephali (Elopiformes. Anguilliformes. and Notacanthiformes). By David G. Smith. July 1979. iv-i- 39 p.. 54 figs.

425. Marine flora and fauna of the northeastern United States. Arihropoda:

Cirripedia. By Victor A. Zullo. April 1979. >'u + 29 p.. 40 figs. For .sale by the Superintendent of Documents, Washington, D.C. 20402, Stock No.

003-017-00453-8.

(427.) Water column thermal structure across the shelf and slope southeast of Sandy Hook, New Jersey, in 1976. By Steven K. Cook. July 1979, p. 231-257,

19 figs.

(427.) Anticyclonic Gulf Stream eddies off the Northeastern United Stales during 1976. By David Mizenko and J. Lockwood Chamberlin. July 1979, p. 259-280, 16 figs., 2 tables.

426. Synopsis of biological data on the rock crab. Cancer irroraius Say. By Thomas E. Bigford. May 1979. v + 26 p.. II figs.. 21 tables.

(427.) River runoff along the Middle Atlantic coast in 1976. By Elizabeth D. Haynes. July 1979. p. 281-287, 1 fig., 1 table, app. 1.

427. Ocean variability in the U.S. Fishery Conservation Zone, 1976. By Julien

R. Goulet, Jr., and Elizabeth D. Haynes, editors. July 1979, iii + 362 p.

(427.) Introduction. By Julien R. Goulet, Jr. July 1979, p. 1-2.

(427.) Summary. By Julien R. Goulet, Jr. July 1979, p. 3-10.

(427.) Atmospheric circulation in 1976. By Elizabeth D. Haynes. July 1979. p. 11-18. 2 figs.

(427.) Atmospheric climatology and its effect on sea surface temperature—

1976. By Robert R. Dickson and Jerome Namias. July 1979. p. 19-33. 6 figs.

(427.) Eastern Pacific sea surface conditions in 1976. By Elizabeth D. Haynes,

July 1979. p. 35-42.

(427.) Climatic conditions related to the fish kill and anoxia off New Jersey during the summer of 1976. By Reed S. Armstrong. July 1979, p. 289-300,

5 figs.

(427.) Variations in the position of the shelf water front off the Atlantic coast between Georges Bank and Cape Romain in 1976. By John T. Gunn. July 1979,

p. 301-314, 8 figs., 1 table.

(427.) Temperature structure on the continental shelf and slope south of New

England during 1976. By R. Wylie Crist and J. Lockwood Chamberlin. July

1979, p. 315-335, 2 figs., app. 1.

(427.) Continuous plankton records: Zooplankton and net phytoplankton in

the Mid-Allantic Bight, 1976. By Daniel E. Smith and Jack W. Jossi. July 1979.

p. 337-348. 7 figs.

(427.) Sea surface conditions in the western North Atlantic in 1976. By Julien R. Goulet. Jr.. and Elizabeth D. Haynes. July 1976, p. 43-50.

(427.) Siphonophore ("lipo") swarming in New England coastal watersupdate, 1976. By Carolyn A. Rogers. July 1979. p. 349-352, I fig.

(427.) Anomalies of monthly mean sea level along the west coasts of North and

South America. By Dale E. Bretschneider and Douglas R. McLain. July 1979. p. 51-64,6 figs.

(427.) Bottom-water temperatures in the Gulf of Maine and on Georges Bank

during spring and autumn. 1976. By Clarence W. Davis. July 1979. p. 353-362. 6

figs.. 3 tables.
NOAA Technical Report NMFS Circular 440

Marine Flora and Fauna of

the Northeastern United States.

Turbellaria: Acoela and

Nemertodernnatida

Louise F. Bush

July 1981

Marine Biological Laboratory 1 LIBRARY

OCT 14 1992

Woods Hole, MassJ

U.S. DEPARTMENT OF COMMERCE

Malcolm Baldrige, Secretary

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Terry L, Leitzell, Assistant Administrator for Fisheries
FOREWORD

This NMFS Circular is part of the subseries "Marine Flora and Fauna of the Norlheastern United StatesI' which consists of original, illustrated, modern manuals on the identification,

classification, and general biology of the estuarine and coastal marine plants and animals of the northeastern United States. The manuals are published at irregular intervals on as many taxa of

the region as there are specialists available to collaborate in their preparation.

Geographic coverage of the "Marine Flora and Fauna of the Northeastern United Slates" is planned to include organisms from the headwaters of estuaries seaward to approximately the 200 m depth on the continental shelf from Maine to Virginia, but may vary somewhat with each major

taxon and the interests of collaborators. Whenever possible representative specimens dealt with in the manuals are deposited in the reference collections of major museums of the region. The "Marine Flora and Fauna of the Northeastern United States" is being prepared in col- laboration with systematic specialists in the United States and abroad. Each manual is based

primarily on recent and ongoing revisionary systematic research and a fresh examination of the

plants and animals. Each major taxon, treated in a separate manual, includes an introduction,

illustrated glossary, uniform originally illustrated keys, annotated checklist with information when available on distribution, habitat, life history, and related biology, references to the major

literature of the group, and a systematic index. These manuals are intended for use by biology students, biologists, biological

oceanographers, informed laymen, and others wishing to identify coastal organisms for this

region. Often they can serve as guides to additional information about species or groups. The manuals are an outgrowth of the widely used "Keys to Marine Invertebrates of the Woods Hole Region;' edited by R. I. Smith in 1964, and produced under the auspices of the Systematics Ecology Program, Marine Biological Laboratory, Woods Hole, Mass. .^fter a sufficient number of manuals of related taxonomic groups have been published, the manuals will be

revised, grouped, and issued as special volumes, which will consist of compilations for phyla or groups of phyla.
CONTENTS

Introduction 1 Diagnostic characters of the order Acoela 1 Diagnostic characters of the order Nemertodermatida 5 Ecology 5 Collecting and examination methods 6

Glossary 7 Key to the families and genera of Acoela and Nemertodermatida of the world 9 Annotated systematic list of North Atlantic species of the Acoela and Nemertodermatida 58

Selected bibliography 64

Systematic index 67 Acknowledgments 70

Coordinating editor's comments 71

The National Marine Fisheries Service (NMFS) does not approve, rec- ommend or endorse any proprietary product or proprietary material

mentioned in this publication. No reference shall be made to NMFS, or

to this publication furnished by NMFS, in any advertising or sales pro- motion which would indicate or imply that NMFS approves, recommends

or endorses any proprietary product or proprietary material mentioned

herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS

publication.

Marine Flora and Fauna of the Northeastern United States.

Turbellaria: Acoela and Nemertodermatida

LOUISE F. BUSH'

ABSTRACT

This manual contains an inlroduction lo the general biology, an illustrated key to the genera, and an annotated systematic list of the orders Acoela and Nemertodermatida. The key facilitates identification of 16 families and 75 genera of Acoela and includes the 3 genera of the order Nemertodermatida. I he systematic list includes 173 species which have been described from the North Atlantic, including some more southern species that might

be encountered here, and gives the habitat and known distribution for each species.

INTRODUCTION

Acoel turbellarians are almost exclusively marine, and only

two species, Oligochoerus linwophilous Ax and Dorjes, 1966 and Limnoposthia polonica Kolasa and Faubel, 1974, have

been described from freshwater and none from any terrestrial

habitat. They are common on various substrata, both intertidally and subtidally, on the continental shelf. A few are

pelagic, but none have been reported to date in deep seas. Most of the work on this order, aside from the series of papers

by Marcus (1950, 1952, 1954) in Brazil, has been carried out by

scientists working on collections made in Europe, and new

species and genera from these areas are being added even to- day. Relatively few species have been described from the northeast coast of the United States, but experience and

materials collected thus far indicate that many, if not most, of

the genera present in the eastern North Atlantic are also represented in the western North Atlantic. Therefore, in order

for this publication to be most useful in the northeastern United States, I have included all known genera from the world in the key and all genera and species from the North

Atlantic are included in the systematic list. The known species

of the order Nemertodermatida, all of which are marine, are

also from the North Atlantic. The position of Acoela in the class Turbellaria has undergone

various changes and, while almost always being recognized as a

natural division, they have been ranked variously as a subclass (Graff 1904a, b), a suborder (Karling 1940, under order Archoophora), or an order (Ax 1956; Dorjes 1968a; Karling

1974). The ranking of Acoela as a separate order has the advantage of conforming to the common usage of the term "acoel" and is so used here. The separation of the order Nemertodermatida from Acoela is a more recent development as is explained below. The subdivisions of Acoela have not been generally agreed upon. Graff (1882) recognized two families, Proporidae and

Aphanostomidae (= Convolutidae). Luther (1912) retained Proporidae and Convolutidae as major subdivisions of the group based on the presence or absence of a seminal bursa, and

this arrangement into two principal families was more or less followed by other workers until the series of papers by Westblad

'George M. Gray Museum, Marine Biological Laboratory, Woods Hole, MA

02543.

appeared (1940, 1942, 1945, 1946, 1948). Westblad in his final paper proposed the division of Acoela into three tribes; Opisthandropora-Abursalia, Proandropora-Abursalia, and

Proandropora-Bursalia, with a series of families included in each tribe. As the names imply, these were based on the position

of the male genital pore and on the presence or absence of the seminal bursa. Recently, Dorjes (1968a), in his comprehensive

survey of Acoela, criticized Westblad's arrangement in detail and simply divided the order into 1 5 families, based primarily on

the structure of the male organs. This avoids at least some of the problems and inconsistencies of Westblad's system and is the arrangement, with the following exceptions, which I have used

in this paper. An additional family, Antroposthiidae, has been

defined recently by Faubel (1976) and is included here as the 16th family. Also, it must be noted that two of Dorjes' families, Hofsteniidae and Nemertodermatidae, have been considered by some authors to deserve ranking as orders separate from

Acoela; recent discussions by Ax (1961), Karling (1967, 1974), Tyler and Rieger (1977), and Faubel and Dorjes (1978) lead me

to agree that certainly Nemertodermatidae do not belong in Acoela since they have a gut cavity during at least part of their

life cycle and also have unitlagellate sperm which are distinctly different from those of Acoela. Specimens of Neinertoderma

sp. taken by me in Vineyard Sound near Woods Hole, Mass.,

clearly show a gut space in some of the specimens. Observations on Meara (Westblad 1949), and on Flagetloplwra (Faubel and

Dorjes 1978), which have open guts and characters close to Neniertoderma, also indicate that the family should be in a

separate order. 1 concur with the proposals for an order Nemertodermatida (Westblad 1947; Karling 1940), and am placing

Nemenoderma. Meuru, and Flagellophora in the order Nemertodermatida. 1 am indicating the possibility of Hofsteniidae

deserving placement in a separate order by a footnote in the key.

Although future work may be expected to add to the families, genera, and species of Acoela, publication of this key to families and known genera should be useful to workers in our area and

encourage students on this side of the Atlantic to further work on the Turbellaria in general and Acoela in particular.

DIAGNOSTIC CHARACTERS OF

THE ORDER ACOELA

The order Acoela, as the name implies, comprises those members of the class Turbellaria which do not have clearly
defined, large open spaces in the body. They not only lack a body cavity, as is the case in all Platyhelminthes, but they also do not possess a digestive cavity with a lining of epithelial cells. The act of digestion is carried out in the central part of the body

in a tissue which appears under the microscope as a meshwork

of vacuolated cytoplasm with scattered nuclei. This central

(digestive) parenchyma is surrounded by a denser tissue, the

peripheral parenchyma, in which are imbedded the organs making up the hermaphroditic reproductive system of these animals. Surrounding the peripheral parenchyma, and more or

less penetrating it, are several layers of muscle fibers and various

epithelial gland cells. The exterior of the body is clothed by a

layer of ciliated epithelial cells. The muscle fibers, epithelial

gland cells, and outer epithelium form a complex that gives stiff- ness and preserves the shape of the animal. The German term "hautmuskelschlauch" (outer muscle sheath), often used in the

literature, applies only to the layers of muscles, but the epithe- lium and its often in sunken nuclei and derived gland cells together with the muscle layers make a more or less interwoven

unit which can be thought of as an outer body wall. The brain

(cerebral ganglion) and large nerve chords lie in the peripheral

parenchyma, or, in a few species, in the base of the outer

epithelial layer. There are no skeletal or excretory systems. As in many marine fiatworms, protonephridia are not present. The acoels are small animals from ~0.5 to ~ 10.5 mm in length,

mostly oval to elongate oval in shape and without striking sur- face features such as appendages or special markings. They tend

to be more or less transparent or white or pale in color, although

a few species are conspicuously colored by the presence of symbionts or special pigments. The lack of a gut cavity as well as of

defined body spaces, usually the lack of conspicuous internal organs aside from those of the reproductive system, and the presence of a uniform parenchyma around the organs give them

a homogenous appearance that enables the animals to be rather

easily distinguished from other Turbellaria. Under low

magnification, other characters are visible which aid in distinguishing acoels, namely the presence of a statocyst, the simple mouth opening without a pharynx or with a very simple

tubelike one, and the arrangement of large eggs full of stored food material (Fig. 1). Location of the mouth and location and

arrangement of sperm and the male copulatory complex (and of

stored sperm in the female parts of some species) are useful for recognizing families and genera. Diagnostic characters which

require observation with the higher powers of the microscope or recourse to the making of histological sections include details of

the reproductive system, presence or absence of frontal or other glands, arrangement of muscle fibers in the outer body wall, and

type of nervous system.

The presence of a statocyst is not unique to the acoels but

this, together with the lack of a conspicuous pharynx and

digestive tract and the presence of large egg cells, is a certain clue

to their recognition. The circular clear vesicle of the statocyst with an enclosed statolith is easy to see in the anterior end of the

living animal, but it is harder to find in fixed material. In sec- tions it is found lying close to or imbedded in the anterior

(cerebral) ganglion.

The mouth in acoels is difficult to see, since in most species it

is simply a break in the outer epithelial layer closed by a few

sphincter muscle fibers. It opens directly into the central

digestive parenchyma (Fig. 2). In relatively few genera, there is a simple tube-shaped pharynx (pharynx simplex) (see Figs. 7, 8, 9, 23a, 24a)2 which is essentially an invagination of the outer body

wall layers. This lack of a speciaUzed pharynx is characteristic of

the Acoela as compared with the other orders of Turbellaria,

^References in the remainder of this section, unless otherwise indicated, are to the examples

in the key where the structures are listed or are indicated by arrows on the figures.

frontal glancj

male germina

center

mouth

mature egg

sperm entering

seminal vesicle.

statocyst

.female

germinal center

seminal bursa

copulatory organ

Figure 1.— Generalized diagram of moel siruclurc. as seen in surface vie» , when llie lurhellarian is sHimmin|> ur ijuiel under a co>erslip.
each of which is defined by a particular and usually more complex pharynx structure. The highly vacuolated central paren- chyma can be seen in sections to be more or less sharply distinct from the denser peripheral parenchyma. The terms "en- docytium" and "ectocytium" have been used for these two

tissues since cell membranes are hard to distinguish in them. However, since some recent studies with electron microscopy

have shown that many turbellarian tissues, once thought to be

syncytial, are truly cellular, the use of these as general terms may

be appropriate no longer. See Ax (1961) for a long discussion of

this point and also Boguta and Mamkaev (1972) and Ivanov and

Mamkaev(1977).

The parts of the hermaphroditic reproductive system are important in identification of genera and species. In the key, an attempt has been made to use only parts which can be

determined without sections, but this is not always possible.

The female parts of an acoel may consist of only the developing and mature eggs. Thus female accessory organs may be

totally lacking or there may be present an organ for storing and

releasing sperm received from a partner (a seminal bursa or bursa seminalis). In a few species, a vagina is present. There are no

oviducts in any of the acoels. The large size of the mature egg is due to its being entolecithal, i.e., each egg develops and stores

nutritive material (yolk) in its cytoplasm. Entolecithal eggs are found in some other turbellarian orders (Archoophora), but the more usual condition in so-called higher Turbellaria

(Neoophora) is for smaller ectolecithal eggs with the nutritive materials developed and stored in separate and conspicuous

yolk glands. Thus the acoels lack yolk glands although in a very few species, Hallangia proporoides, Polychoerus caudatus,

Nadina pulchella, and some species of Oligochoerus, a group of

yolk-carrying cells near the eggs have been described. Thus, in most acoels, the eggs increase in size gradually as they mature and yolk accumulates so that a series of eggs of increasing sizes can be seen arranged conspicuously along the length of the body. The youngest stages are found in a definite area of the body (a female germinal center) that is characteristic for each

species. This germinal center may be considered to be the ovary although there is no ovary wall or delimiting capsule and the center may be more or less diffuse. The term "ovary" is

variou.sly used in the literature to indicate either the germinal

center or the entire mass of developing eggs. In some species, there may be a common germinal center where both eggs and sperm start their development in close proximity and then move

apart as they mature (Fig. 16). The seminal bursa may be only a

loosely defined vacuolated space in the parenchyma (Fig. 138) or

it may be a more or less elaborate structure with epithelial or muscular walls (Figs. 29, 30). Nozzles (Figs. 42, 43) or spermatic ducts (Figs. 62, 63) or bursal appendages (Figs. 99, 100, lOI) may be present. The bursa may open directly from the female pore (Figs. 69, 99), from a common genital pore (Fig. 30), or from an associated female antrum or vagina (Fig. 29). Groups

of sperm associated with bursal nozzles may also be found in the parenchyma without any discernible outside connection (Figs. 46, 72a, 72b) in which case it may be postulated that sperm are stored in this way after they have been deposited either on the

outside of the body or through the epidermis by hypodermic

injection. However, it has been suggested also that sperm

deposited in a vagina or antrum may move through the wall to form such a disconnected bursa or to lie in vacuolated spaces in the parenchyma.

The sperm develop in a male germinal center (testis) which,

like the ovary, is not delimited by a definite wall. The developing

stages may be arranged in a rather compact mass, may appear to be organized in follicles as in some other Turbellaria, or may be more or less scattered ("diffuse testis"). Distinctions between

these types of testes and their exact definitions are not clear (see Steinbock 1966:84-85). As already noted, the male and female germinal centers may be closely associated. In most cases, however, the sperm develop dorsal to the eggs and move

posteriorly in the dorsal parenchyma, since there are no sperm

ducts in the male system of the acoels. Some sort of male copulatory complex is always present although it may consist of nothing more than a space in the parenchyma where sperm accumulate close to a male genital pore (Fig. 74). Such an unwalled space in the parenchyma where sperm accumulate before ejaculation is termed a "false seminal

vesicle" and such may occur not only with a simple genital pore, but also with many other types of copulatory apparatus (Figs.

80, 169, 171). A waUed structure where sperm are accumulated

male germinal center digestive parenchyma

frontal gland seminal bursa

sperm entering

seminal

vesicle

statocyst

bocJy parenchyma

female germinal center

mouth

mature egg cell

female antrum

male antrum

Figure 2. —Generalized diagram of acoel siructures, longitudinal reconstruction.

3
is considered a true seminal vesicle (Figs. 18, 26a, 91); inside of

this type there is usually present, besides the sperm, a granular

secretion supplied by the walls of the vesicle or by associated gland cells. Arrangements for the ejaculation of sperm in the acoels range from a simple outside opening at the end of a true or false seminal vesicle to more complex situations that include a passage to the outside (male antrum) and a well-developed

penis. The penis, when present, may be composed of various arrangements of fine or coarse needles (Figs. 32b, 54, 106), may

consist of a cone-shaped group of muscles (Fig. 107), or may be a glandular or muscular tube (Figs. 91, 94, 115). In some cases,

it is inverted into the seminal vesicle itself when at rest and

everted to the exterior when sperm are to be discharged. It may

be enclosed by a penis sheath or sac which may also enclose the seminal vesicle. A special feature of some families is cuticular

needles (adenodactyls) which do not make up a penis, but which

are associated with the reproductive passages and which

apparently have a stimulatory function (Figs. 37, 38). The sperm of acoels are biflagellate (Hendelberg 1977) and

internal fertilization is the rule, as in other Turbellaria. The

arrangement of the reproductive organs suggests cross fertilization. Behavior that suggests mutual insemination has been

observed a number of times and it has been shown conclusively

to be the case by histological sections of animals in coitus (Hyman 1937, in Amphiscolops langerhansi; Westblad 1946, in Conaperta jlavibacitlum). Asexual reproduction has been reported several times, but has been shown clearly to be a normal method only for the species Paratomella unichaeta (Dorjes 1966) and Pseudohaplogonaria

macnaei (du Bois-Reymond Marcus 1957). Acoels have rather

limited powers of regeneration, a characteristic which is un- doubtedly associated with the lack of asexual reproduction. A

summary of studies on regeneration in this order is given by

Steinbock (1967) and should be referred to for its bibliography

as well as for his view of the evolutionary significance of exper- iments in this area. Gland cells and their secretions play an important role in the physiology of acoels judging by their large numbers and

frequent occurrences. Some types of gland cells are so conspicuous as to be useful in the identification of species. Most obvious are those whose secretions are released onto the surface of

the body. Rhabdites are common, and under the microscope

they can be seen as small elongate bodies lying in or close to the outer epithelial layer. They are produced in the epithelium or in

special epithelial cells which are sunken below the surface but which retain their connections to the surface so that the rhabdites may be extruded to the outside. Rhabdites may be

scattered irregularly over the body, be present only in limited

areas, or be arranged in beautiful rows running the length of the animal. Often they are colorless, but they may carry color that

gives a characteristic hue to the entire animal. Rhammites are more elongated or irregular bodies lying deeper in the interior of

the body.

A group of gland cells makes up the frontal gland which is

characteristic of and occurs in most acoels as well as in some

other turbellarians. This gland may not be conspicuous in living

animals, but in stained preparations it appears as a varying

number of differentially staining cells with ducts opening close together at the anterior tip of the body. In some cases, the ducts

unite to form a small ampule before opening to the outside.

Studies of the detailed structure of this gland suggest that it is involved in chemoreception as well as in secretion (Antonius

1970). Other gland cells are present in association with the reproductive organs. There do not appear to be any special digestive

glands, although some gland cells may be developed around the mouth or pharynx (Fig. 14). Adhesive glands in conspicuous

papillae, as in some other turbellarians, are not usually present, but groups of special adhesive cilia, "haptocilial' in Hesioliciurn inops, have been described recently (Tyler 1973; Crezee and

Tyler 1976). Some cells in the parenchyma that produce pigment

would be classed as gland cells.

In most species a layer of circular muscle fibers lies to the outside next to the epithelium with alayer of longitudinal fibers just

inside this (Fig. 130). In the few genera where this arrangement

is reversed, it is considered to be of taxonomic significance and

has been used to define at least one genus (Fig. 128). There may

also be a third layer of fibers arranged diagonally between, or

close to the others, and sometimes there is an additional layer of

circular fibers (Bush 1975). Other fibers, probably derived from

these, form the sphincter around the mouth, and, in the reproductive system, muscle fibers are arranged as sphincters,

retractors, protractors, and as sheets in the walls of some

organs. In many acoels, muscle fibers that extend through the parenchyma from side to side are only weakly developed so that movement is restricted mostly to elongations or shortenings of

the body with only a limited amount of twisting or coiling.

Locomotion in these species is a characteristic gliding movement

accomplished by means of the cilia on the surface. However, in some species, intraparenchymal muscles are better developed

and act as retractors of the anterior or posterior ends, may be

used in rolling the sides of the body ventrally as when capturing

prey, or, in some interstitial species, provide more varied coiling

and twisting of the body as the animals move about in spaces between the sand grains.

The nervous system of acoels has been described in relatively few species since the nerve tissue is usually not clearly differentiated in routine sections. In most acoels, however, it can be seen

that there is a more or less complex cerebral ganglion lying in the parenchyma at the anterior end of the body with three to six nerve chords extending posteriorly. Some smaller nerves extend

to the surface at the anterior end, to the statocyst, and to the neighborhood of the frontal gland. In a few species of acoels and in the order Nemertodermatida, all or part of the nerve

tissue, instead of lying in the parenchyma inside the outer wall muscle layers, is found instead lying next to or even somewhat

intermeshed with the bases of the outer epithelial cells. Such an

epithelial nervous system is considered by some authors to repre- sent a primitive situation and is, therefore, held to be of importance in plotting the evolutionary changes and relationships of

the Turbellaria. For differing opinions on this point, see discus- sions by Ax (1961) and Karling (1974). Sensory structures appear to be rather few and simple, but, since most of them must be represented by single cells, they are not usually identified and are probably more numerous than is

realized. Observations of the reactions of living animals indicate

that among the cilia there may be sensory hairs, but acoels do

not have the large conspicuous sensory hairs, or the ciliated pits or grooves found in some other turbellarians. Only a few species

have pigmented eye spots or pigment-cup ocelli. Electron microscopy will undoubtedly give needed information on sen- sory structures (e.g., the recent work by Crezee and Tyler (1976) on the caudal organ in Hesioliciurn inops).
The life cycles of acoels have been determined mostly by inference from collection data. For more complete information,

laboratory culture of the animals is required, and this has rarely been done. A recent report by Ax (1977) gave an account based on collection data for 14 species of acoels, as well as other

Turbellaria, from the North Sea Island of Sylt. He concluded

that in 12 of the 14 acoels there is a polyvoltine life cycle (i.e., with more than one generation per year). Also, he noted that "the polyvoltine life cycle is an important prerequisite for the immense population development of several interstitial acoels.

In addition the brood size for acoels commonly consists of many

eggs:' Apelt (1969) cultured successfully several species of acoels through at least one generation. He followed the embryological

development, and his observations agree with those of earlier workers showing that the acoels have a spiral-duet type of

cleavage. He also shows the speed of development to be directly

related to temperature. Almost all acoels are oviparous but Apelt mentions a few viviparous species. All have a direct type

of development without larval stages. See the review by Henley

(1974) for a good summary of earlier work on acoel reproduction.

DIAGNOSTIC CHARACTERS OF

THE ORDER NEMERTODERMATIDA

The order Nemertodermatida includes two genera, Nemertoderma and Meara, which were originally included in the Acoela, plus a recently defined genus, Flagellophora, which

appears to be related to the first two and which is therefore also included in this order. All these species are small forms whose

general appearance and habits made it natural when they were

first observed to assume they were acoels. However, the

uniflagellate sperm in Nemertoderma and Meara (Tyler and

Rieger 1975; Hendelberg 1977) and the presence of a gut cavity

at least some time during their life history differentiate these genera from acoels. The presence of two statoliths instead of one in the statocyst makes the distinction between nemertodermatids and acoels relatively easy, the only reported cases of two

statoliths in acoels being in fusion and regenerated specimens

(Steinbock 1966). The known species of Nemertoderma and

Flagellophora are free-living sublittoral forms; Meara is represented by one species from the gut or body cavity of

holothurians. The size range for nemertodermatids is from ~0.5 to ~3.0 mm.

They are generally without conspicuous external features except

that in Nemertoderma bathycola the thick outer epithelium has

very large vacuoles so that under low magnification the living animal appears to have a shining outer layer. While the other known nemertodermatids are generally oval in form, Nemertoderma rubra is a typical interstitial form with an elongated

body and a coiling, twisting type of movement. The digestive tract is a somewhat variable cavity lined by an

epithelium that includes two types of cells, amoeboid digestive

cells and club-shaped gland ("kornerkolben") cells, with coarse

granules in their cytoplasm. These gland cells are considered to be an important characteristic of the order. The mouth, located on the ventral side, may have slightly thickened lips as in Meara

or an inturned short section of the epithelium as in Nemertoderma, but in Flagellophora it appears to be lacking

altogether. This last genus is characterized by a flagellar organ

(Fig. 181a, b) which reaches from the anterior end to the neighborhood of the gut and which may take the place of a

mouth in securing food, but there is little known about the habits of this species.

As already noted, the nervous system in the Nemertodermatida is epithehal or subepithelial. A mass of nerve tissue at the

anterior end just under or closely associated with the epithelium

represents a cerebral center. Associated with the epithelium all over the body there is a generally diffuse nerve plexus which

thins out toward the posterior end and which also shows

longitudinal thickenings that probably function as longitudinal

nerves. Aside from the statocyst, sense organs have not been

described. The reproductive systems in the Nemertodermatida are

relatively simple and similar to those in the acoels. Testes and

ovaries may be represented by a common germinal center or may be clearly separated as compact or follicular units. Female

accessory organs are lacking in Nemertoderma and Meara, but

in Flagellophora there is a large seminal bursa which opens dorsally at the center of the body. The male pore is located in the posterior end of the body, ventrally in Flagellophora and ter- minally in Nemertoderma and Meara. In Nemertoderma there is a long male antrum with a seminal vesicle and a mass of

associated glands. In Meara the antrum is shorter and the seminal vesicle is smaller and without conspicuous glands. In Flagellophora there is a short male antrum with only a false seminal vesicle. The eggs, as in Acoela, are entolecithal but, as already noted, the sperm are uniflagellate in contrast to the

biflagellate sperm of the acoels.

ECOLOGY

Little is known concerning the ecology of the acoels and even

less about the nemertodermatids for whom we have only the evidence from collection records. Certainly the acoels are more common and occur in a wider variety of habitats than the nemertodermatids. As noted above, our records for the nemertodermatids are all from sublittoral habitats or, in the case of Meara, as entocommensals from holothurians. The acoels are common subtidally on the surface of sand or sandy mud or

intertidally in rock pools and among detritus or algae in shallow

water. Neither group can withstand drying and their soft bodies seem to prevent their burrowing within soft mud deposits;

relatively few species have been found associated with the interstitial fauna of sandy beaches ahhough more are being described from this habitat as it is being explored further. A few species of

acoels are pelagic and some acoels have been classed as parasitic

(probably commensals) since they are found on, or in the body

spaces of, larger animals. Laboratory studies which determine accurately the kind and

range of factors to which these animals react await their culture

in vitro. The recent work by Apelt (1969), which has been mentioned above, gives the best example of quantitative data. Observations on behavior are found scattered in the literature. The role played by acoels in animal communities may be

inferred from their food relationships as well as from the numbers present in any one area. Food items may be determined

in some specimens from remains found in the digestive paren- chyma. Many species of acoels seem to be predators or

scavengers, much the same as other turbellarians. In spite of

small size and fragile bodies acoels may be fast swimmers; I have

observed Neochildia fusca moving very quickly to overwhelm

prey such as small worms, crustaceans, and other small in- vertebrates. When young, members of this species are found to
contain diatoms almost exclusively, but they shift to the role of

active predators as they grow larger and mature. In some

habitats acoels are only a small part of the biological community

structure, but often they are present in enormous numbers (Ax

1977). In such cases they must play a significant role in the food

web of the community.

COLLECTING AND EXAMINATION METHODS

The small size and rather fragile body structure of both the

acoels and the nemertodermatids present difficulties in their collection and study. Both their fragility and small size result in most species not being recovered by general sampling techniques such as benthic nets or sledges. Relatively undisturbed samples

of bottom materials, algae, or other plant materials which are brought into the laboratory and processed there give the best

results. The most effective methods for processing are: 1) allow- ing natural concentration of the specimens at the surface of

bottom samples or at the surface of the overlying water after

standing, 2) washing out or sieving of specimens with or without

the use of narcotic solutions, and 3) seawater ice treatment. A

few of the larger or more conspicuous species (e.g., Polychoerus

caudatus, a bright orange species) may be collected by hand

from stones or shells in the intertidal zone. The seawater ice method has been shown to be superior for quantitative analysis

of interstitial species (Uhlig et al. 1973). Some species which normally live on or near the surface of the substratum tend to go downwards when disturbed and many

become mixed with the substratum in spite of care in collecting.

If the substratum samples or masses of algae or other plants are allowed to stand in the collecting water in the laboratory,

however, many of the animals concentrate at the surface of the substratum or at the surface of the water. The length of time

necessary for this to occur may vary from a few hours to a day

or so. Apparently, the animals are reacting to lack of oxygen in lower layers, although change of temperature may also be

involved. They may be picked up from the surface with a medicine dropper, either with or without the aid of a dissecting scope.

Washing out of specimens from the substratum may be done

in several ways. Vigorous shaking of algae or other plant material in seawater will dislodge some specimens. Vigorous stirring of sand samples in seawater followed by quick decanting of

the water as sand particles settle will recover many specimens

since neither the acoels nor the nemertodermatids have the strongly developed adhesive organs found in some other

turbellarians. For most interstitial organisms a narcotizing solution (usually 7% MgCl2 in tap water) is used so that the animals

may be passively washed out by stirring and decanting, by sieving, or by elutriation of the material in a separation funnel (see Hulings and Gray 1971, for an account of various methods). On

replacement of the narcotizing solution the animals recover

readily if they have not been left in the narcotic too long, but

acoels tend to die very soon and also to break up when handled

in the relaxed state. If the material is fixed and stained with a general stain, such as Rose Bengal, before washing out, this difficulty is avoided, but the process of sorting afterwards is much

more difficult since most turbellarians, and especially acoels and

nematodermatids, look like small oval lumps after fixation and

can be easily mistaken for broken bits of tissue or for ciliates which may be about the same size. The seawater ice method is an effective method (Uhlig et al.

1973) for recovering Turbellaria brought into the laboratory with sand or sandy mud and is being adopted by many workers

who desire a quantitative analysis of such material. This method

involves the use of a temperature and water salinity gradient to induce the animals to leave the substratum. A simple apparatus

(Fig. 3) is set up consisting of a tube to hold the substratum samples plus seawater ice which provides a slight temperature

gradient but, more importantly, results in a change from low to high salinity of the water that runs through the sample as melting occurs. The live animals collect in the dish at the bottom

of the apparatus and can then be sorted and prepared for further study. The chief drawback of this method is that it is somewhat time consuming and may not be worthwhile if only a quick determination of the most prominent members of a fauna

is desired.

tube holcJerinsulation.

secJiment.

culture (dish

with sea water.

V / l\/

X

.plastic tube

sea-water-ice

nylon gauze

rubber bancj or

ig

dish

/^ ruDoer oan

ri---^^'^ plastic rin(

I

n petri

.overflow

Figure 3.—Apparatus for seawater ice treatment of sediment (redrawn from Uhlig et al. 1973). Use of the insulation layer is optional.

6
Acoels may be kept in small dishes in the laboratory for

hours, days, or even months. In plain seawater many species will

live for a day or so. However, adding a bit of substratum may

provide enough food for them to live much longer, and when

food preferences are known they may be maintained through at

least part of a life cycle. Eggs are often laid by mature aduhs

during the first few days in dishes in the laboratory and young

hatched from such a "culture" may survive for a time even

without further feeding. Apelt (1969) maintained several species

by supplying cultured diatoms to the animals and was thus able

to study the complete life cycles.

For the easiest identification by use of the following key, it is

best to begin with living animals. In some cases fixation and

perhaps sectioning will be necessary after the living animals have been observed. Where only fixed material is available, whole mounts are of some help but in most cases sectioning is

necessary. Observation of Hving animals is done in a drop of water under

a coverslip with the amount of water adjusted so that the

coverslip just slightly flattens the acoel, thus holding the animal

quiet and also flattening the body to achieve greater

transparency. A narcotic such as MgCU may be added to the drop of water, but the difference between achieving just strong

enough a solution of the narcotic to quiet the animal and too

strong a solution which kills it and causes it to disintegrate is very narrow. Such treatment is difficult to use with acoels. Flat- tening of the animal may also be achieved by the use of a

specially built "rotocompressor" such as Heunert and Uhlig

(1966) described but, so far as I am aware, these are not

available commercially. The larger structures referred to in the key and many of the finer details of organs such as the seminal bursa may be observed by study of living animals with ordinary low power (ICX) x ) or high dry (430 x ) magnification. The use of phase contrast or interference contrast is best for studying these transparent animals, but is not essential.

Fixing of materials for further examination may be done with any of the standard histological fixatives. The one most com- monly used, especially in field work, is hot or cold Bouin's since specimens may be left in this for an indefinite period of time.

Fixation with this solution, although not considered as good for

cytological details, is quite satisfactory for routine identification. Animals can be picked up in a finely drawn-out medicine

dropper with as httle water as possible and dropped directly into

the fixative. For animals as small as most species of these two

orders, the fixation is almost instantaneous, and there is

relatively httle contraction or shrinking of the specimens.

Specimens fixed in Formalin with other animals, plant material,

or both may be used, but the fixation is poor and often specimens are distorted or broken. Whole mounts may be stained in Borax Carmine which is pro- bably best for museum specimens since it does not fade as much

as many of the hematoxyUns. However, I have had better dif- ferentiation with a trichrome stain (stock solution:

Chromotrope 2R, 0.6 g; Fastgreen FCF, 0.3 g; phosphotungstic

acid, 0.7 g; acetic acid, 1.0 ml; distilled water 100.0 ml. See Horen 1957), if it is used in a very dilute solution. For this, specimens which have been fixed in Bouin's (10-20 min) should be washed (several changes for about 1 h) in 70% alcohol. After washing they are left in the dilute stain overnight, then dehydrated and mounted. For the best whole mounts, animals should be fixed by allowing the Bouin's to flow over the animal

held slightly flattened under a coverslip.

For sections, any of the standard histological methods may be

used. Imbedding in paraffin and sections 6-10 fi m thick has proved satisfactory. Various stains may be used, but since the

structure of acoels depends almost entirely on the structure of

individual cells, the most satisfactory stains will be those which

bring out as clearly as possible the nuclei and shape of cells and

muscle fibers. For this the old standby, a combination of iron hematoxylin with a counterstain such as eosin or orange G, is

still the most reliable. Mallory's triple stain is fairly good, but many of the stains for special tissues used in histology are not

effective since acoels do not have such specialized tissues. The

use of electron microscopy is producing much needed information about these animals but cannot be used primarily for identification of species.

GLOSSARY

Terms are defined here as used in this key; included are some

equivalent terms common in the literature. Terminology used

for reproductive organs has varied considerably in the past and

definitions given here are an attempt to render in English the most recent usageofDOrjes (1968a), Antonius(1968), and other European workers.

Accessory organs Organs which aid in reproduction as accessories to the ovary and testis. Adenodactyl A bundle of fine cuticular needles lying with

inner ends in the wall of the male antrum and with points

projecting into the antrum; the inner ends are associated with gland cells. Functions as a stimulatory ("reizorgan") or adhesive organ; compare "prostatoid organ!'

Antrum See "female antrum," "male antrum" (in some

authors "atrium" is used instead of "antrum."

Archipharynx A type of pharynx unique to the family Nadinidae; consists of a short ciliated outer section and long,

funnel-shaped inner part; the wall of the outer section has muscle fibers which are extensions of those of the outer body

wall; the wall of the inner section has an added inner layer of

very heavy circular muscles; a sphincter muscle separates the two parts. Atrium See "common genital atrium!' Bursal appendage An appendage on the seminal bursa; see "spermatic duct." Bursal nozzle A cuticularized structure associated with the seminal bursa or with groups of stored sperm.

Bursal sphincter See "spermatic duct." Bursa seminatis Same as seminal bursa. Central parenchyma See "parenchyma."

Common genital atrium Passage leading from the exterior to both male and female reproductive organs. Common genital pore Opening from the exterior to both

female and male reproductive organs; may be associated with

a common genital atrium or the male and female parts may

open directly from it. Common germinal center The site in some species where the

early stages of both eggs and sperm are intermingled or lie close together. Ductus spermaticus Same as spermatic duct. False seminal vesicle See "seminal vesicle." Female antrum Passage leading to the female organs which is considered to be an inpocketing of the outer body wall as
indicated by an epithelial lining that is continuous with and

similar to the outer epithehum.

Female accessory organs Organs in the female beside the ovary and eggs; in the acoels these consist of the seminal bursa and

associated parts, but may be lacking altogether.

Female germinal center Area where the earliest stages of devel- opment of eggs are found; in the acoels it is not delimited by

a capsule and is continuous with the string of eggs which move along the body as they develop; "ovary" is often used

to include both the germinal center and the string of eggs. Flagellar organ Organ consisting of several flagella in an

elongated channel at the anterior end of the body in some members of the order Nemertodermatida. The flagella arise in an oval enlargement at the proximal end of the channel and

may be protruded through the open end of the channel at

the anterior tip of the body.

Frontal gland Group of gland cells whose ducts open at the

anterior end of the body either singly or variously combined,

with or without a small ampule at the outer end of the ducts. Germinal center See "female germinal center," "male germinal center." Haptocilia Specialized cilia with adhesive tips. K'Ornerkolben cells Large club-shaped gland cells with coarse

secretory granules; characteristic of the intestine of the Nemertodermatida.

Male antrum Passage leading to the male organs which is considered to be an inpocketing of the outer body wall as

indicated by an epithelial lining which is continuous with and similar to the outer epithelium.

Male copulatory complex All organs involved in the transfer of sperm to a partner. This includes the penis and associated glands and ducts. Male germinal center Area where the earliest stages of sperm

development take place; not set off by a wall or capsule and

may be scattered groups of cells; "testes" often used for

this general area. Nozzle See "bursal nozzle." Outer body wall Includes the outer epithelial layer and the underlying circular, longitudinal, and, if present, oblique muscle layers plus intermingled parenchyma and gland

cells. Ovary Includes the female germinal center and the string of

developing eggs; see "female germinal center." Parenchyma The mass of generalized cells filling most of the body in acoels; peripheral parenchyma is the outer part of this mass which surrounds the body organs; the central paren- chyma is the more vacuolated central part in which digestion

occurrs. Penis Glandular, muscular, or cuticularized structure which

serves directly to convey sperm to the partner; a wide variety of structures are included under this term. Penis sac Sac, not part of the wall of the penis, that surrounds

the penis and may also surround the seminal vesicle and, in a few cases, the male antrum also. Peripheral parenchyma See "parenchyma."

Pharynx simplex A simple tube that structurally is an inturned

part of the outer body wall. Prostatoid organ A thick-walled pocket containing a secretion and, sometimes, with a cuticularized point or needle at its open end; may open either into the male antrum or onto the ventral surface of the body; believed to function as a stimulatory ("reizorgan") or adhesive organ; compare

"adenodactyl."

Rhabdites Oval to elongate-oval rods, secreted by, and lying

in, outer epithelium or in epithelial cells sunken into the parenchyma; may be clear, semitransparent, or colored and

may protrude on the surface of the body.

Rhammites Similar to rhabdites but long, sinous, or irregular

in shape and always found in cells sunken into the paren- chyma.

Seminal bursa Walled sac that receives and stores sperm from

a partner. Seminal vesicle Area where sperm accumulate before ejaculation; a true seminal vesicle is a walled organ associated with

the male copulatory organ; a false seminal vesicle is simply a space in the parenchyma associated with the copulatory organ or the male genital pore. Spermatic duct Duct leading from the seminal bursa; may

be outside of the bursa (bursal appendage) or may be inverted inside the bursa; may be cuticularized (bursal nozzle) or may consist only of cellular and /or muscular elements; may act as a sphincter. Its evolutionary precursor appears to be only a cap of cells (see Dorjes 1968a:73-74).

Statocyst Sense organ in anterior end of body. In Acoela it is composed of a cellular vesicle which contains a lithocyte

enclosing a statolith; in Nemertodermatida it is similar but

contains two lithocytes, each with a statolith. Syncytial bursa Area in the parenchyma where bundles of sperm received from a partner accumulate and which thus

serves as a bursa in addition to or in the place of a seminal

bursa.

Testis See "male germinal center." True seminal vesicle See "seminal vesicle." Vagina Passage leading to the seminal bursa whose lining

epithelium and wall structure does not correspond to that of a

female antrum, or where a passage is present in addition to

the female antrum; this term is loosely used and not well

defined.
KEY TO THE FAMILIES AND GENERA OF ACOELA AND NEMERTODERMATIDA

OF THE WORLD

This key includes the known families and genera of the world

since the acoels in the western North Atlantic are poorly known,

and anyone working with material from the northeastern United

States will need to start by comparing specimens with the

families and genera already described from other areas. Particularly pertinent are the genera from the eastern North Atlantic since we already know that many of the same genera and some of the same species also occur here. New genera are being defined from time to time, and some appearing very recently,

since the key was completed, are added by means of footnotes at appropriate places.

The arrangement of the famihes and parts of the key are based on DOrjes (1968a) and the debt owing to him is gratefully

acknowledged, but I am responsible, of course, for the key and

systematic list as here presented.

In identifying material it is most desirable to start with a study

of living specimens slightly flattened under a coverslip; the identification to genus often can be made in this way. When this does not suffice, the only recourse is to fix the animals and make

sections as suggested on page 7. Unfortunately, in my experi- ence, whole mounts satisfactory for identification purposes are very difficult to attain. The inclusion of a complete diagram for

at least one species in each genus will facilitate identification and

the annotated systematic list of species for each genus will provide further clues. Page references in the key after each family

refer to its location in the systematic list. All figures in the key

have been redrawn from the original descriptions so far as possi- ble and the type species for each genus is included in all but a few cases. Except where otherwise noted, all figures are sagittal reconstructions of the entire animal or of male and female

accessory organs. Arrows on the figures indicate characters

listed in the key.

Statocyst absent—three instances are reported where statocyst is lacking in species otherwise having the characters of Acoela: Amphiscotops sargassi Hyman from Bermuda; Amphiscolops evelinae Marcus from Brazil; Haplodiscus piger Weldon from the North Atlantic (Fig. 4).

Figure 4. —Haplodiscus piger, dorsal view.

1 Statocyst present 2

2 (7) Statocyst with more than one statolith (Fig. 5) Order NEMERTODERMATIDA

.

Figure 5.—Anterior end, dorsal view.

.87

Figure 6. —Anterior end, dorsal view.

2 (J) Statocyst with only one statohth (Fig. 6) . .Order ACOELA 3
3 (2) Mouth with pharynx simplex opening terminally at the posterior end of the body (Fig. 7) Family DIOPISTHOPORIDAE (p. 60)

,

Genus Diopisthoporus.

Figure 7.

Diopisthoporus longitubus.

3 (2) Mouth opening with or without a pharynx but not terminal at the posterior end of the body

4 (i) Mouth with pharynx at the anterior end or very close to front end and with male pore at posterior end of body (Fig. 8). Archiproporus minimus An der Lan has been placed in Proporus (Westblad 1945) but is now

considered to deserve ranking in a separate genus (Karling 1974:8); description of this species is unclear on some points and position of the genus seems to me uncertain (Fig. 9) Family PROPORIDAE (p. 58) Genus Proporus.

Genus Archiproporus.

Figure 8. —Proporus venenosus.

®@~^^-^\3

Figure 9. —Archiproporus minimus.

4 (i) Mouth opening with or without a pharynx but not terminal at anterior end of body, or, if terminal or subter- minal at anterior end, then male pore not terminal at posterior end

10
5 (4) String of developing eggs extends behind the male copulatory organ into the posterior end of the body (Figs.

10, 11)

Figure 10. —Diagramalic longitudinal section. C^^,

(^^^^'-^^

Figure 11. —Diagramalic longitudinal section.

5 (.4) String ofdeveloping eggs ends anterior to or at the level of the male copulatory organ (Fig. 12) 13

Figure 12. —Diagramalic longitudinal section.

6 (5) Mouth with a pharynx simplex (Fig. 13) Family SOLENOFILOMORPHIDAE (p. 63)

Figure M.—OUgofilomorpha intersliliophilum: a-sagittal reconstruction; b-sagittal section of phar>nii.

6 (5) Mouth without a pharynx

11

.11
7 (6) Rhammites absent

7 (6) Rhammites present (see Figs. 17, 18) 10

8 (7) Wreath of large cells present around the mouth (Fig. 14)

. Genus Myopea.

Figure 14.

Myopea crassula: a-dorsal view; b-sec(ion through mouth and pharynx; c-male and female accessory organs.

(7) No wreath around the mouth although glandular epithelium of the pharynx may vary in thickness

9 (8) Seminal bursa present (Fig. 15) (see also Fig. 13)

. Genus Oligofilomorpha.

Figure 15.

Oligofilomorpha karlingi.

9(5) Seminal bursa absent (Fig. 16)

. Genus Solenofdomorpha.

Figure 16.

Solenofilomorpha longissima.

12
10 (7) Rhammites scattered near the entire ventral surface but concentrated around the mouth; seminal vesicle very

large so as to almost fill the body in cross section; male antrum with a network of longitudinal muscles running through it (Fig. 17) Genus Fusanlruin.

Figure 17.

tusantrum rhammiphorum.

10 (7) Rhammites in rhammite tracts anterior to the mouth; seminal vesicle and male antrum well defined with muscle fibers in the walls (Fig. 18) Genus Endocincta.

Figure 18.Endocincta punctata.

1 1 (6) Male pore in anterior of body close to mouth; tubelike ciliated male antrum (Fig. 19) Family ANTIGONARIIDAE (p. 62)

Figure 19.—Antigonaria arenaria.

1 1 (6) Male pore not in anterior end; male antrum absent; haptocilia present (Fig. 20) Family PARATOMELLIDAE (p. 61).

13

.12
12 (//) A caudal sensory organ present (Fig. 20); no asexual reproduction..Genus Hesiolicium.

@ y^^iC> -ip~^ < f^'

haptocilia

Figure 20. —Hesiolicium inops.

12 (//) Caudal sensory organ absent (Figs. 21, 22); both sexual and asexual reproduction

Genus Paratomella.

(TOO, 0^ o<\,0' r cv"

Figure 21. —Paratomella unichaela.

Figure 22.—Paratomella rubra, sagittal section through body at level of male accessor) organs.

13 (5) Mouthopeningat or close to the anterior end of body 14

13 (5) Mouth opening not close to anterior end 18

1 4 (/i) Male pore close to mouth at anterior end; bursa seminalis absent

14 {13) Male pore not close to mouth; bursa seminalis present ....

Family HOFSTENIIDAE' (p. 61) 15

Family HALLANGllDAE (p. 60) 17

'The Hofsteniidae are sometimes placed in an order or suborder separate from the Acoela (e.g.. Karling 1940). However, until this point has been resolved by further studies, the tendency at present appears to be to retain them in the Acoela (see Steinbock l%6, for a complete review of this question).

14
15 {14) Pharynx long, tube-shaped, thick, and muscular; mouth opening subterminal at anterior end (Fig. 23) Genus Hofstenia.

Figure 23.

Hofstenia atroviridis.

15 (14) Pharynx with only weakly muscular walls, either tube-shaped or short and globular; mouth opening ventral near anterior end 16

16 (15) Pharynx long (about one- fourth body length), thin and tube-shaped (Fig. 24a); seminal vesicle enclosed in a

thick muscular wall which encloses also the cuticular elements of the penis (Fig. 24b). One species from the Mediterranean Genus Hofsteniola.

Figure 24.

Hofsteniola pardii.

16 (15) Pharynx short (about one-sixth body length), thin-walled and globular (Fig. 25'a); seminal vesicle clearly separated from the bulb of the penis by a constriction (Fig. 25b). One species from .Brazil Genus Marcusio/a.

Figure 25.Marcusiola tinga.

15
\1 (14) Penis and seminal vesicle well developed (Fig. 26); free-living .Genus Hallangia.

Figure 76.—Hallangia proporoides.

17 {14} Penis and seminal vesicle reduced (Fig. 27); parasitic; from the Caspian Sea Genus Aechmalolus.

Figure 27. —Aechmalolus pyrola: a-dorsal view; b-cross section of

copulatoo' organs.

18 (/J) Mouth with archipharynx (Fig. 28) y^ «'«.. -^-v^-j.

. . . Family NADINIDAE (p. 61) y^ /2> . "^.^

1 Genus Nadina. ( /^^^ ^. ^^ Co) ) /f^^\

Figure 1i.—Nadina pulchella. ^^ ' — *v ? ^

18 (/i) Mouthwithpharynxsimplexor without a pharynx 19

_ vagina

19 {IS) Seminal bursa present, opening posterior to the male iff —

copulatory organ either through a common genital pore \ vV /'//^^^^^^^^'^X ^^^

or through a separate female pore (Figs. 29, 30) \ V^^/ i'W // -%-"// Family OTOCELIDIDAE (p. 61) 20 V^B^ Ud uf^fE

Figure 29. —Olocelis wesibladi.

16
Figure 30.—Archocelh macrorhabdilis.

\9 (18) Seminal bursa present or absent but when present opening

anterior to the male copulatory organ 25

20 (19) Bursal nozzles present 21

20 (/9) Bursal nozzles absent 23

2 1 (20) Testes paired and the two ovaries fused (Fig. 3 1 a); penis muscular (Fig. 31b)

Genus Nolocelis.

Figure il.—.\oloceUs guUmarensis: a-dorsal view; b-sagitlal reconstruction of male and female accessor> organs.

21 (20) Testes and ovaries paired (Fig. 32a); penis muscular (Fig. 33b) or with cuticular needles (Fig. 32b) .22

Figure 32.Philocelis ceUala: a-dorsal view; b-sagiltal reconstruction of male and female accessory organs.

^Genus Exocelis, recently described from the Galapagos Islands, has many small nozzles, a feature which makes it easily distinguishable from the other genera of the Otocilididae. Also, the

seminal bursa in this genus lies caudal to the male organ, a situation found in no other acoel.

Figure 31c.

Exocelis exopenis.

17
22 {21) Penis with cuticular needles (Fig. 32) Genus Philocelis.

11 {21) Penis a muscular tube (Fig. 33) Genus Otocelis. ^ 7. rzr-^r^::--...,,.,^^^ vagina

Figure 33. —Otocelis ruhropuncfata: a-dorsal view; -b-sagiltal reconstruction of male and female accesson organs.

23 {20) Ovary paired (Fig. 34a); two coiled spermatic ducts present (Fig. 34b). One species from Brazil Genus Haplocelis.

penis

?

Figure 34. —Haplocelis dichone: a-sagittal reconstruction; b-sagittal reconstruction of seminal bursa.

23 {20) Ovary unpaired; spermatic duct lacking or very short .24

24 (23) Spermatic duct lacking; common genital pore terminal at posterior end (Fig. 35a, b) .

.

Genus Archocelis. Genus Parotocelis.-

seminal bursa

penis

Figure 35a. —Archocelis macrorhabdilis.

'Genus Parolocelis, recently described from the Galapagos Islands, is reponed as being close to Archocelis and would fall here in the key. It differs from Archocelis in having a shon ciliated male

antrum and a muscular penis papilla surrounded by a crown of gland cells. In Archocelis a male antrum is lacking and the muscular wall of the seminal vesicle appears to serve as a penis.

18
Figure iSb.—Paroiocelis luleopunclala.

24 (23) Spermatic duct very short; common genital pore ventral (Fig. 36)

seminal bursa

Genus Haploiestis.

vagina

spermatic duct penis

Figure 36. —Hapiotestis curvitubus.

female antrum

25 {19) Male antrum with adenodactyls bearing large needles and conspicuous rosettes of gland cells (Figs. 37, 38); one exception, see Genus Paranaperus Family ANAPERIDAE (p. 61) .26

Figure 37.—Anaperus Ivaerminnensis, dorsal and sagittal views of

posterior end. Figure 38. —Achoerus pachycaudalus, dorsal and sagittal views of posterior end.

25 (/P) Male antrum without adenodactyls or with adenodactyls very small and gland cells very inconspicuous

(Figs. 39, 40) .30

Figure 39.

Kuma monogonophora^

dorsal view of posterior end.

Figure 40. —Haptoposthia rubra.

19
26 (25) Either colored rhabdites or epithelial pigment present 27

26 (25) Colored rhabdites and epithelial pigment lacking; adenodactyls very small. This genus is taxonomically connected to both Anaperidae and Haploposthiidae but is placed here in Anaperidae by Dorjes (1968a) (Fig.

4}) Genus Paranaperus.

Figure 41.

Paranaperus pellucidus: a-sagillal reconstruction; b-dorsal view of posterior end.

27 (26) Seminal bursa and bursal nozzles lacking

27 (26) Either seminal bursa with a nozzle (Fig. 42) or nozzles without walled bursae (Fig. 43) present

.28

.29

li ii

Figure 42.

Philachoerus johanni. Figure 43.

Anaperus tvaerminnensis.

28 (27) Color provided by rhabdites (Fig. 44) .Genus Achoerus.

mMmM^

Figure 44.

Achoerus pachycaudalus.

28 (27) Color provided by epithelial pigment granules (Fig. 45). Single species from Brazil Genus Pseudanaperus.

20
Figure 45.

Pseudanaperus linclus: a-sagillal section; b-dorsal view of male accessory organs.

29 (27) One to many bursal nozzles present but walled seminal bursae absent (Fig. 46) Genus Anaperus.

Figure 46.

Anaperus gardineri: a-dorsal view; b-dorsal view of male

accessory organs and bursal slniclures.

29 (27) A well-developed seminal bursa with a cuticular nozzle (Fig. 47) .Genus Philachoerus.

Figure 47.

Philachoerus johanni.

21
30 (25) Male organ simple; penis either lacking (Figs. 48, 49) or very weakly developed (Fig. 50) or its place taken by a

ciliated male antrum invaginated into a sheath or sac (Fig. 51) .31

%3

Figure 4S.—Parahaploposthia avesicula.

Figure SO. —Haploposthia rubra.

Figure 49. —Haplogonaria simplex.

?

rfFigure 51. —Convoluella brunea.

30 (25) Male organ well developed; either a glandular cellular penial area associated with the seminal vesicle (Fig. 52) or a tube-shaped penis (Fig. 53) or a cuticularized penis stylet (Fig. 54) .46

Figure Sl.—Pseudmecynoslomum granulum. Figure 53.—Archaphanosloma macrospiriferum. Figure 54.—Actinoposihia haplovala.

31 (30) Male organ simple; penis lacking or very weakly developed .

22

.32
31 (30) Male organ consists of a ciliated male antrum which is

inserted at its proximal end into a sheath or sac in such

a way that it opens directly from an unciliated granular

vesicle with either a true or false seminal vesicle present

(Fig. 55) FamUy ANTROPOSTHIIDAE (p. 64) ... . .43

Figure 55.

Convoluella bnmea.

32 (31) Male organ with a very small penis. Two species, Haploposthia rubra (Fig. 50) and Haploposthia ( = Kurnal)

albiventer (Fig. 86) with other characters which have placed them in the Family Haploposthiidae have very small penes. Paranaperus pellucidus (Fig. 41) with a very small penis and small adenodactyls appears to be

taxonomically intermediate between the Family Anaperidae and the Family Haploposthiidae.

32 (31) Penis lacking (Figs. 56, 57, 58); often with a tube-shaped male antrum which is not inserted into a sheath or

sac (Figs. 57, 58) Family HAPLOPOSTHIIDAE (p. 60) 33

Figure 56. —Pseudohaplogonaria vacua. Figure 57.

Kama monogonophora, dorsal view of posterior end. Figure 58'.Parahaplogonaria maxima.

33 (32) Seminal bursa present either with a distinct wall (Fig. 59) or as a more or less well-defined vacuolated or syncytial space in the parenchyma (Fig. 60) 34

Figure 59.

Haplogonaria elegans. ^

Figure 60.—Pseudohaplogonaria vacua.

33 (32) Seminal bursa lacking 38

23
34 (33) Either no cuticular nozzle on the seminal bursa (Fig. 61 ), or an attached (Fig. 62), or an invaginated (Fig. 63) muscular spermatic duct may be present instead 35

Figure 61. —Haplogonaria glanduiifera. Figure 62. —Pseudokuma orphinum. Figure 63. —Parahaplogonaria maxima.

34 (33) A cuticular nozzle present either on a seminal bursa (Fig. 64), or near the vacuolated space serving as a bursa (Fig. 65) 37

Figure 64.

Deuterogonaria Ihauma. Figure 65.

Pseudohaplogonaria slylifera.

35 (34) Seminal bursa without a nozzle and without a spermatic duct (Figs. 66, 67, 68). See also Figures 59, 61 Genus Haplogonaria.

Figure 66.

Haplogonaria minima.

24
Figure 61.—Haplogonaria simplex. Figure t».—Haplogonaria macrobursaUa.

35 (34) Seminal bursa without a nozzle but with either an invaginated or an attached muscular spermatic duct .36

36 (35) Muscular spermatic duct invaginated into the seminal bursa; false seminal vesicle present close to male pore

(Fig. 69) Genus Parahaplogonaria.

Figure 69.

Parahaplogonaria maxima.

36 (35) Muscular spermatic duct not invaginated; true seminal vesicle present. One species from Brazil (Fig. 70) Genus Pseudokuma.

Figure 10.— Pseudokuma orphinum.

25
37 {34) Seminal vesicle with a separate glandular area present on one side; seminal bursa well developed with a

strongly cuticularized nozzle (Fig. 71). One species from Brazil Genus Deulerogonaria.

Figure 11.—Deulerogonaria ihauma: a-dorsal view; b-sagillal reconslruction of male and female accessor) organs.

37 (34) Seminal vesicle lacking or only weakly developed; seminal bursa weakly developed or lacking but a weakly

cuticularized nozzle always present (Figs. 72, 73) Genus Pseudohaplogonaria.

Figure 72. —Pseudohaplogonaria vacua.

Figure 73.

Pseudohaplogonaria stylifera.

26
38 {33) Male antrum, penis, and seminal vesicle all lacking; a false seminal vesicle present at the posterior end of the body (Fig. 74) Genus Simplicomorpha.

Figure 74.

SimpUcomorpha gigantorhabditls.

38 (33) Male antrum present (Figs. 75, 76) .39

Figure 75.Kuma monogonophora^ dorsal view of posterior end. Figure 76.Parahaptoposthia avesicula, sagittal section of posterior end.

39 (38) Semiglobular caudal organ present, consisting of a ciliated inpocketing of the terminal end of the body which

is surrounded by and into which open gland cells containing pear-shaped droplets of secretion (Fig. 77) Genus Adenocauda.

Figure 77.

Adenocauda helgolandica.

39 (38) Caudal organ lacking 40

27
40 (39) Frontal organ lacking (Figs. 78, 79)

,

. Genus A/ronta.

Figure 78.

Afronta aurantiaca, dorsal view

Figure 79.Afronta rubra; a-sagillal

reconslniction; b-dor^al

view of posterior end

40 (39) Frontal gland present 41

41 (40) A pair of false seminal vesicles present (Figs. 80, 81) .Genus Parahaptoposthia.

Figure 80.

Parahaptoposthia cerebroepitheliata.

4 1 (40) Either a true seminal vesicle or a single false seminal vesicle present

Figure 81.

Parahaptoposthia avesicuta,

42

42 (41) Colored by rhabdites or stored body pigment; common germinal center for eggs and sperm (Figs. 82, 83) Genus Haploposthia.

28
figure 82.

Haploposthia rubra.

Kit^ure 83.

Haploposthia rubropunctata.

42 (41) Colorless; separate germinal center for eggs and sperm (Figs. 84, 85, 86) Genus Kuma.

Figure 84.Kuma monogonophora,

dorsal view of posterior end

Figure 86.Kuma albivenler.

43 (31) Prostatoid organ present at male pore; seminal bursa with a cuticularized nozzle (Fig. 87) Genus Adenopea.

Figure 87.

Adenopea illardatus: a-dorsal view; b-sagillal recoitstruc

tion of accessorj organs.

43 (31) Prostatoid organ absent; seminal bursa either lacking or, if present, without a cuticularized nozzle

29

.44
44 (43) Seminal bursa lacking (Fig. 88) .Genus Unanira.

Figure 88. —Unanira polyvacuola.

44 (43) Seminal bursa present 45

45 (44) Seminal bursa with a cellular nozzle (Fig. 89) .Genus Antroposthia.

Figure 89.

Aniroposlhia unipora.

45 (44) Seminal bursa with a small cap of cells, rather than a nozzle (Fig. 90)Genus Convoluetla.

Figure 90.ConvoiueUa brunea.

30
46 (30) Copulatory organ a globular structure inside of which is a proximal seminal vesicle and a distal glandular

region which serves as a penis (Figs. 91, 92) Family MECYNOSTOMIDAE (p. 63) ,47

Figure 91. —Mecynostomum haplovarium, sagittal section.

Figure 92.—Pseudmecynoslomum pelophilum: a-dorsal vi«w of posterior end; b-sagittal section of copulatory organ.

46 (30) Copulatory organ either a conical penis made up of cellular, muscular, or cuticular parts (Fig. 93), or a tube- shaped penis formed by an invagination of the body wall (Fig. 94) 52

Figure 93. —Aclinoposlhia hapluvata: a-dorsal view of posterior end; b-sagittal

section of copulatory organ.

Figure 94.—Anhaphanostoma macrospirifemm: a-dorsal view of posterior end; b-sagiltal

section of copulatory organ.

31
47 {4g) Seminal bursa lacking (Figs. 95,96). .Genus Mecynostomum.

Figure 95.Mecynostomum auriium.

Figure %.

Mecynostomum haplovarium.

47 (46) Seminal bursa present 48

48 (47) Seminal bursa lacking an appendage (Fig. 97); in Pseudmecynostomum mahtimum the bursal wall develops a protrusion over the ripe eggs (Fig. 98) Genus Pseudmecynostomum.

Figure 91.—Pseudmecynostomum pelophUum. Figure 98.—Pseudmecynostomum maritimum.

32
48 (47) Seminal bursa with a cellular (Fig. 99), muscular (Fig. 100), or cuticular (Fig. 101) appendage 49

Figure 99.—Postmecynoslomum pklum. Figure 100.—Pwamecynoslomum diversicolor. Figure lOl.—Paedomecynoslomum bruneum.

49 (48) Appendage cuticular 50

49 (48) Appendage cellular or muscular 51

50 (49) Seminal bursa weakly developed without a well-defined wall but with spermatic duct strongly cuticularized to form a conspicuous nozzle (Fig. 102) Genus Paedomecynostomum.

Figure 102.—Paedomecynostomum bruneum.

50 (49) Seminal bursa well developed with an appendage formed of matrix cells whose inner ends are weakly

cuticularized to form a weak nozzle (Fig. 103) Genus Philomecynostomum.

. ? Hj*ure 103.

f'/iihmecynosionium lapUlum.

33
51 {49) Appendage of bursa muscular; rhabdites present; variegated coloring from dissolved pigment and yellow to brown granules (Fig. 104) Genus Paramecynostomum.

Figure VM.—Paramecynostomum diversicolor.

5 1 (49) Appendage of bursa cellular; rhabdites absent; no dissolved or granular pigment (Fig. 105) Genus Postinecynostomum.

Genus LimnoposthiaJ'

Figure 105a.—Poslmecynoslomum picium.

Figure iOSb.—Limnoposthia polonka. (See next page and text foolnole 6.)

*The genus Limnoposlhia (Kolasa and Faubel 1 974) was placed lenlalively by the authors close lo Conmliila. bul it seems to me the illustrations and descriptions of the penial structures would

lead a user of this key to a position close to Puslmccymislmmum. The structure of the penis in the illustration of Limnoposlhia polonica suggests the glandular penis of Poslmecynoslomum and the pan labeled "vas deferens" may conespond lo the enclosed seminal vesicle of the Mccynostomidae, Study of actual specimens is needed to clear up this point. From freshwater lake in Poland.

34
Figure 105c, d.

Limnoposthia polonica.

52 (46) Copulatory organ with a cone-shaped penis built up of cuticular (Fig. 106), or muscular (Fig. 107 elements and never invaginated into a seminal vesicle Family CHILDIIDAE (p. 62) .53

Figure 106. —Paraphanostoma macroposlhium. Figure 107.—Paraproporus diovatus.

52 (46) Copulatory organ with a tube-shaped, muscular and often glandular penis. This may be simply a direct invagination of the body wall without a male antrum or true seminal vesicle (Fig. 108), or it may be combined with

either one or both of a male antrum or a seminal vesicle. It is often invaginated into or surrounded by the seminal vesicle (Fig. 109) or a penis sac (Fig. 110) Family CONVOLUTIDAE (p. 58) .63

Figure 108.—Proconvoluta primitiva.

y^k'O

Figure 109, —Pseudaphanostoma psammophUum.

35

Figure 110.—Haphdiscus bockL
53 (52) Seminal bursa lacking; a syncytial area in the parenchyma, which serves as a bursa, may be present

.

53 (52) Seminal bursa present

.54

.58

54 (53) Two copulatory organs present (Fig. 111). .Genus Childia.

Figure III. —i hiUtUi ^nienUttulka: a-dursal view; b-cupulator> organ.

54 (53) A single copulatory organ 55

55 (54) A rosette of muscles, fine cuticular needles or glands at the distal end of the seminal vesicle appears like a penis but may serve as a stimulatory organ (Figs. 1 12, 1 13) .... Genus Paraproporus.

Figure 112. —Paraproporus rubescens.

36
Figure 113. —Paraproporus diovatus.

55 (54) Copulatory organ not a rosettelike arrangement; penis with strongly cuticularized needles (Fig. 1 14), muscle

layers in its wall (Fig. 1 15), or a cuticularized papilla surrounded by matrix cells (Fig. 116) .56

Figure 114.—Actinoposthia longa. Figure 115. —Actinoposthia pigmental. Figure 1 16.—Atriofronttt polyvacuola.

56 (55) Male antrum long, tube-shaped and ciliated; penis a thin cuticularized tube clothed in matrix cells (Fig. 117) Genus A triojronta.

Figure 117. —Atriofronta polyvacuoia.

56 (55) Male antrum short; penis with cuticularized stylet needles or muscle layers in its wall

.

37

.57
57 (56) Seminal vesicle present; large cyanophile gland cells absent (Figs. 118, 1 19, 120, 121) . . .

.

Genus Aclinoposthia.

Figure 118.—Aclinoposthia caudaia: a-sagillal reconstruction; b-dorsal view of posterior end.

Figure 119. —Aclinoposthia haplovata. Figure 120.—Actinoposthia longa, dorsal view. Figure 121. —Actinoposthia pigmentea.

57 (56) Seminal vesicle lacking; large cyanophile gland cells surround the copulatory apparatus (Fig. 1 22) Genus Microposthia.

Figure 122. —Microposthia tistensLv. a-sagiltal reconstruction;

b-dorsal view; c-male accessory organs.

38
58 (53) Seminal bursa with a cuticularized nozzle

(Fig. 123) 59

Kiguiv 123.

Philaclinoposlhia saliem.

58 (53) Seminal bursa lacking a cuticularized

nozzle .60

59 (58) Four copulatory organs present

(Fig. 124) Genus Tetraposthia.

Figure 124.— Tetraposthia colymbetis.

59 (58) A single copulatory organ present (Figs. 125, 126)

.

. Genus Philactinoposthia.

Genus Monoposthia.^

Figure I25a.

Philactinoposthia saliem.

Figure 12Sb.Monoposlhia pseuduvesicula. (See text foolnote 7.) Figure \2(>.—Philaclinoposlhia adenogonaria.

'Genus Monoposlhia, recently described from ihe Galapagos Islands, is close lo Ihe genus Philactinoposthia bul lacks a true seminal vesicle, such as is present in Philactinoposlhia.

39
60 (58) Outer body wall muscle layers consist of outer longitudinal and inner circular layers (Fig. 128); frontal gland

very small or lacking (Figs. 127, 129) Genus Paraphanosloma

.-longitudinal muscle

o " " " " ° '^circular muscle

Figure 128. —Longitudinal section of body wall.

Figure 129.

Paraphanosloma gracilis.

60 (55) Outer body wall muscle layers with outer circular and inner longitudinal fibers (Fig. 130); frontal gland well developed 61 mMMmmkMmL

;o j^, ^° J ° r ^^circular muscle

ooo_aooo°oa ^ _|onqitudinal muscle

Figure 130. —Longitudinal section of body wall.

61 (60) Seminal bursa without a spermatic duct (Fig. 131)

.

. Genus Pseudactinoposthia.

Figure \i\.— Pseudactinoposthia saltans.

40
61 (60) Seminal bursa with a cellular (Fig. 132) or muscular (Fig. 133) spermatic duct 62

Figure 132.Archactinopostbia pelophUa.

Figure Mi.—Pelophia pachymorpha.

62 (61) Spermatic duct muscular, invaginated into the seminal bursa and directed posteriorly (Figs. 1 34, 1 35) Genus Pelophila.

Figure 135.Pelophila pachymorpha.

62 (6J) Spermatic duct cellular, not invaginated, directed anteriorly (Fig. 136) Genus Archaclinoposlhia.

-Archactinoposthia pelophila.

41
63 (52) Seminal bursa present as either a definite walled structure (Fig. 137), or as a network of syncytial tissue in the parenchyma (Fig. 138) 64

Figure 137.—Bursosuphia baltaUmaniaformia. Figure 138.

Archaphanostoma hislobursaUum.

63 (52) Seminal bursa lacking 79

64 (63) Seminal bursa an extensive syncytial area in the posterior end of the body with bundles of sperm scattered

therein (Figs. 139, 140, 141) Genus Archaphanostoma.

Figure 139.Archaphanostoma agile.

Figure 140.

Archaphanostoma macrospiriferum.

64 (63) Seminal bursa a definite walled structure ....

Figure 141.—Archaphanostoma histobursaiium.

.65

42
65 (64) Plate-shaped, planktonic (Fig. 142). Until Dorjes (1970) de.scribed Haplodiscus bocki, members of this genus had been reported to lack a seminal bursa, so this genus is retained under both headings in this key (.see 79

(63), Fig. 168) Genus Haplodiscus.

Figure 142. —Haplodiscus bocki: a-dor^al view; i>-sagitlal reconslruction; c-sagitlal reconstruction of male and female accessor)' organs.

65 (64) More or less elongated in shape, benthic .66

66 (65) Cuticularized nozzle present as an appendage on the seminal bursa (Fig. 143) 67

Figure 143. —Conaperta norn-egica.

66 (65) Cuticularized nozzle absent; spermatic duct invaginated into the seminal bursa may be cuticularized (Fig.

144) 73

Figure 144. —Postaphanostoma atriomagnum.

43
67 (66) One bursal nozzle or a spermatic duct present 68

67 (66) Two to many bursal nozzles present "70

68 (67) Male and female genital pores separate 69

68 (67) Common genital pore present (Figs. 145, 146) Genus Conaperta.

Figure 145.

Conaperta thela.

Figure 146.

Conaperta norxegica.

69 (6S) Tube-shaped penis surrounded by a muscular seminal vesicle; bursal nozzle present (Fig. 147) Genus Convoluta.

44
Figure 147.

Convoluia convolula.

69 (65) Small tube-shaped penis with a false seminal vesicle attached at proximal end; cellular spermatic duct present. From Red Sea (Fig. 148) Genus Brachypea.

Figure 148.

Brachypea kenoma.

70 (67) Special yolk-carrying cells absent; yolk deposited in the eggs 72

70 (67) Developing eggs in one layer toward the ventral

side of the body with a layer of special yolkcarrying cells (yolk-glandlike layer) dorsal or dorsolateral to the eggs (Fig. 149) 71

Figure 149.

Polychoenis, cross section.

45
71 {70) Body teardrop-shaped with pointed posterior end; two to eight pairs of prostatoid organs present (Fig. 150). One freshwater and several marine species from Caspian Sea region

Genus Oligochoerus.

Figure 150. —Oligochoerus Umnophilus.

71 (70) Body deeply notched at posterior end with one to three thin tails in the notch; prostatoid organs lacking (Fig. 151) Genus Polychoerus.

Figure 151. —Polychoerus caudatus, dorsal view.

46
72 (70) Separate genital pores; colored by the presence of symbionts or pigment; seminal bursa with two, more or less curved or spiraled nozzles (Figs. 152, 153, 154) Genus Ainphiscolops.

Figure \Sl.—Amphiscolops langerhansi. dorsal view. Figure 153.

Amphiscolops cinereus, seminal bur^.

Figure 154.—Amphiscolops bermudensis: a-dorsal view; b-sagittal reconstniclion of male and female accessory organs.

72 (70) Common genital pore; white, or colored only by the presence of food products; seminal bursa with two or more short cone-shaped nozzles. From the Pacific coasts of the United States and U.S.S.R. (Fig. 155) . .

.

Genus Diatomovora.

F~igure 155.Diatomovora amoena.

47
73 (66) Seminal bursa without a projecting external appendage, but a flattened cap of a few cells (Fig. 156) or an

invaginated spermatic duct (Fig. 157) may be present 74

Figure i56. —I'raecunvolula karinae.

Figure 157. —Poslaphanostoma plum.

13 (66) Seminal bursa with a definite external cellular or muscular (but not cuticularized) appendage (Fig. 158) 77

Figure 158.

Proaphanostoma lenuissima.

14 (73) True seminal vesicle lacking.

74 (73) True seminal vesicle present.

.75

.76

48
75 (74) Small rhabdites present, arranged in rows; female germinal center and string of eggs unpaired; penis a simple,

tube-shaped invagination of the outer body wall (Figs. 159, 160) Genus Poslaphanosloma.

Figure 159.—Postapbanostoma atriomagnum.

Figure 160.Poslaphanostoma filum.

75 (74) Rabdites lacking; female germinal center and string of eggs paired; penis very glandular and invaginated into

a muscular penis sac (Fig. 161) Genus Praeconvoluta.

Figure 161. —Praeconvoluta karinae.

49
76 (74) Seminal bursa opens from a long, tubelike ciliated female antrum and is surrounded by a mass of nellike

tissue (a bursal tissue), but with no appendage (Fig. 162) Genus Bursosaphia.

Figure 162. —Bursosaphia baltalimaniaformis.

76 (74) Seminal bursa opens almost directly from the exterior without any or with an extremely short female antrum; no appendage and no bursal tissue present but there may be an invaginated spermatic duct (Figs. 163, 164) . .

.

Genus Praeaphanostoina.

Figure 163.

Praephanostoma cftaelocaudatum.

Figure 164. —Praeaphanostoma tulheri.

11 (73) Rhabdites present, arranged in irregular rows; seminal vesicle and ciliated male antrum present (Fig. 165)

.

Genus Aphanostoma.

50
Figure 165.—Apha/tosloma album.

77 (73) Rhabdites absent; male antrum lacking; seminal vesicle present or absent 78

78 (77) Seminal vesicle absent; penis a simple invagination of outer wall layers with a ball of sperm at the proximal

end that is surrounded by a parenchymal net with a few muscle fibers and gland cells (Fig. 166) Genus Proconvolula.

Figure 166. —Procnnvoluta primitiva.

78 (77) Seminal vesicle present; penis a tubelike invagination which is further invaginated into the seminal vesicle

(Fig. 167) Genus Proaphanostoina.

Figure 167.Proaphanostoma lenuissima.

51
79 (63) Plate-shaped; planktonic (Fig. 168); until Dorjes (1970) described Haplodiscus bocki, the members of this genus had none of them been reported as having a seminal bursa, so the genus is retained under both headings

in this key (see 65 (64), Fig. 142) Genus Haplodiscus.

Figure 168.

Haplodiscus piger. a-doisal view; b-sagitlal reconstruction.

79 (63) Not broad and flattened but more or less elongated in shape or oval; benthic .80

80 (79) False seminal vesicle present (Fig. 169)

.

.81

Figure 169.

Rimicola glacialis.

80 (79) True semnal vesicle present (Fig. 170) 82

^^

Figure 170.

Pseudaphanostoma psammophiluni

JM

52
il (80) Male antrum lacking; a glandular organ opens at the male pore and close to this at the posterior side of the

penis there is a false seminal vesicle (Fig. 1 7 1

)

Genus Pseudoposlhia.

Figure 171. —Pseudoposthia macrogonopora.

i\ (.80) A short male antrum present; copulatory organ without a glandular organ and with the false seminal vesicle

at the proximal end of the penis (Fig. 172) Genus Rirnicola.

Figure 172. —Rirnicola glaciaiis.

82 (80) Male antrum lacking (Fig. 173); parasitic. Compare Faerlea, 84(55)

Genus A vagina.

Figure 173.

Avagina incola.

82 (80) Male antrum present, although it may be very short .83

53
83 (82) Twocopulatoryapparatusespresent (Fig. 174)

. Genus Neochildia.

Figure 174.X'eochitdia fusca: a-dor^l view; l)-&agittal reconslniction of posterior end.

83 {82) One copulatory apparatus present 84

84 (83) Male antrum very short (Fig. 175). Compare with Avagi/ia 82 (80), which was originally (Westblad 1945)

separated from Faerlea on the basis of the latter being free-living. Description of a parasitic species in Faerlea by Db'rjes in 1972, leaves only the slight differences in the male antra to distinguish these genera. They may

need to be combined Genus Faerlea.

Figure 175.

Faerlea fragUis.

84 (83) Male antrum long, tube-shaped and ciliated 85

54
85 (84) Penisandmaleantrum without a clear line demarking one from the other (Fig. 176); from the Caspian Sea Genus Baltalimania.

Figure 176.

Baltalimania kosswigi: a-dorsal view; b-male accessory organs.

85 (84) Penis and male antrum with a clear line distinguishing one from the other 86

86 (85) Colored rhabdites present as well as other pigment; a tube-shaped organ present at the anterior end as well as

a frontal gland (Fig. 177). From Sakhalin Island, Pacific coast of U.S.S.R Genus Oxyposthia.

Figure IT7.

Oxyposthia praedator.

55
86 (85) Colored rhabdites lacking, but small uncolored rhabdites in rows; tube-shaped organ lacking; frontal gland

present (Figs. 178, 179, 180) Genus Pseudaphanostoma.

Figure 178.

Pseudaphanostoma variabilis.

Figure 179.

Pseudaphanostoma pelophilum. Figure 180.

Pseudaphanostoma psammophUum.

87 (2) Flagellar organ present; mouth opening absent (Fig. 181)

.

. Genus Flagellophora.

Figure \S\.—Hagettophora apelti: a-sagilUi reconstruction; b-base of Hagellar organ next lo inlcsline; c-male accessory organs.

56
87 (2) Flagellar organ absent; mouth opening present

.

.88

88 (87) Frontal gland absent; ovary and testes folicular; male antrum with a side pocket but no gland cells around

base of the seminal vesicle (Fig. 182); commensal in holothurians Genus Meara.

Figure 182.—A/eora slichopL

88 (57) Frontal gland well developed; compact testes and compact ovary; male antrum with many large gland cells around base of the seminal vesicle (Figs. 183, 184); free-living

Genus Nemertoderma.

Figure 183.Semertoderma bathycula.

Figure IM.—Nemertodenna rubra: a-sagillal reconslniction; b-sagittal section through pharynx; c-sagillal section of nuiie accessory organs.

57
ANNOTATED SYSTEMATIC LIST OF

NORTH ATLANTIC GENERA AND SPECIES OF

ACOELA AND NEMERTODERMATIDA

Species listed here include: 1) species reported in the literature

or collected by the author in the area, and 2) genera and species

that may be expected in this area because of their occurrence in

the North Sea, the North Atlantic Ocean, or adjacent areas.

Since the fauna here is as yet poorly described, it is felt to be most useful to include as many of the species and genera likely

to be encountered as possible. Synonyms likely to be encountered in the literature are also included. Most of the doubtful

species I have omitted altogether.

The list is arranged systematically in families as in Dorjes

(1968a) with the new family Antroposthiidae Faubel added at

the end. Genera are arranged alphabetically within the families and species alphabetically within the genera. Geographic

distribution and habitat are indicated for each species. Asterisks

indicate species for which 1 have records or which have been

reported in the literature from the northeast coast of North

America.

Ordpr ACOELA

FamUy PROPORIDAE Graff, 1852

Genus Archiproporus An der Lan, 1936

Archiproporus minimus = Proporus minimus according to Westblad (1945), but see comment under 4 (3) in key.

Genus Proporus O. Schmidt, 1882

Proporus brochii Westblad, 1945. Sweden, Norway. 1(X)-

150 m. Proporus lonchitis Dorjes, \91\. Norway. 50-200 m.

Proporus minimus (An der Lan, 1936). Norway, Greenland.

200-300 m. Proporus rubropunctatus O. Schmidt, 1852 = Otocelis rubropunclata.

Proporus venenosus (O. Schmidt, 1852). British Isles, Mediterranean Sea, Black Sea. Subtidal. Includes subspecies: P. V. venenosus Graff, 1904, P. v. violaceus Graff,

1882, and P. v. viridiflavus Riedl, 1959.

Genus Schizoporus O. Schmidl, 1852

Only one species S. venenosus = Proporus venenosus.

Family CONVOLUTIDAE Graff, 1904

Genus Adenopea moved to Family ANTROPOSTHIIDAE

Genus Amphkhoerus Graff, 1891 = Amphiscolops

Genus Amphiscolops Graff, 1904

Amphiscolops bermudensis Hyman, 1939. Bermuda. On

seaweeds. Amphiscolops cinereus (Graff, 1874). North Atlantic,

Mediterranean Sea. On algae.

'Amphiscolops gardineri Graff, 1910. Graff listed this in his

first report on American Turbellaria, but later (1911) erected the new genus Anaperus for it. Amphiscolops langerhansi (Graff, 1882). North Atlantic,

Mediterranean. Tide pools, rocky shores. A species identified as this (?) was collected on algae at Virginia Key, Fla. Amphiscolops sargassi Hyman, 1939. Bermuda, Brazil. On

seaweeds. Amphiscolops virescens Orsted, 1845 = Aphanosioma

virescens.

Genus Aphanostoma Orsted, 1845

Many species assigned to this genus have been shuffled back

and forth several times. I have followed Dorjes (1968a) as to

their disposition in the following list.

Aphanostoma album Dorjes, 1968. North Sea. From

muddy sand.

*1 Aphanostoma aurantiacum Verrill, 1892. Newport,

R.I. Listed as a doubtful species by various authors and

not definitely identified since. Aphanostoma auritum (M. S. Schultze, 1851) = Mecynostonium auritum. Aphanostoma caudatum (An der Lan, 1936) = Actinoposthia

caudata. Aphanostoma divaceum Verrill, 1892. Listed by Dorjes

(1968a) as a doubtful species. Probably a typographical error on A. olivaceum. *Aphanostoma diversicolor Orsted, 1845 = Paramecynostomum diversicolor. Aphanostoma elegans Jensen, 1878. Northern Europe. On

algae.

Aphanostoma lutheri Westblad, 1946 = Pelophila lutheri. Aphanostoma macrobursalis Westblad, 1946 = Pseudmecynostomum macrobursalium.

Aphanostoma macrospiriferum Westblad, 1946 = Archaphanostoma macrospiriferum

.

Aphanostoma minimum Westblad, 1946 = Haplogonaria

minima.

*1 Aphanostoma olivaceum Verrill, 1892. Provincetown,

Mass. Listed as a doubtful species by Graff (1911) and not reported since. Not found in my collections made there. Aphanostoma rhomboides Jensen, 1878. Some references to

this are really to Archaphanostoma agile (see Db'rjes 1968a:

85, 157). Aphanostoma rubropunctata (O. Schmidt, 1852) = Otocelis rubropunctata.

Aphanostoma tenuissimum Westblad, 1946 = Proaphanosto- ma tenuissima. Aphanostoma virescens (Orsted, 1845). North Atlantic from

White Sea to Greenland.

Genus .Archaphanostoma Dorjes, 1968

Archaphanostoma agile (Jensen, 1878). North Sea, North

Atlantic to Greenland. Common in tide pools and in intertidal zone. Archaphanostoma histobursalium Dorjes, 1968. North Sea. From muddy sand. Archaphanostoma macrospiriferum (Westblad, 1946). North

Sea. On soft bottom, 15-30 m.

58
Genus A vagina Leiper, 1902

A vagina aurita Meixner = Mecynostoinuin aurituin. Avagina glandulifera Westblad, 1953. North Sea in gut of Spaiangus purpureus. Avagina incola Leiper, 1902. British Isles and North Sea in gut of Echinocardium.

Avagina subliioralis Faubel, 1976. North Sea. Subtidal in coarse sand. Avagina (enuissima (Westblad, 1946). DOrjes (1968a) lists this here but later (1972) moves to his new genus Proaphanostoma.

a species whose definition is uncertain; there are many refer- ences in the literature and many reports on experiments with animals identified as this species.

Convoluta saliens Graff, 1882 = Philaclinoposthia saliens. Convoluta stylifera Westblad, 1946 = Philaclinoposthia

stylifera. Convohita sutcliffei Hanson, 1961 = Pseudohaplogonaria

sutcliffei. Convoluta variomorpha Dorjes, 1968 = Conaperia vario- morpha.

Convoluta viridipunctata Westblad, 1946 = Pseudohaplogonaria viridipunctata.

Genus Baltalimania Ax, 1959 Genus Faerlea Westblad, 1945

Baltalimania agile (Jensen, 1878) = Archaphanostoma agile. Baltalimania macrospiriferum (Westblad, 1946) = Archaphanostoma macrospiriferum.

Genus Bursosaphia Dorjes, 1968

Bursosaphia baltalimaniaformis Dorjes, 1%8. North Sea. From shelly sand under algae or in Mytilus colonies.

Genus Conaperta Antonius, 1968

Conaperta flavibacillum (Jensen, 1878). European Arctic and

Atlantic coasts, Canary Islands, Black Sea, Mediterranean.

On algae.

Conaperta norwegica (Westblad, 1946). Norway. 10-50 m. Conaperta variomorpha (Dorjes, 1968). North Sea. From

fine sand or clay, 6-11 m.

Faerlea echinocardii Dorjes, 1972. Norway. In gut of

Echinocardium flavescens. Faerlea fragilis'^ estbldid, \945. North Sea. 30-50 m.

Faerlea glomerata Westblad, 1945. North Sea. 40 m.

Genus Haplodiscus Weldon, 1889

Haplodiscus pigerWe\(ion, \SS9. Pelagic. Bahamas.

Haplodiscus weldoni Bohmig, 1895. Pelagic. Sargasso Sea.

Genus Neochildia Bush, 1975

"Neochildia fusca Bush, 1975. North Carolina to Maine.

In or on sand or muddy sand along marsh streams or in

estuaries.

Genus Polychoerus Mark, 1892

Genus Convoluta Orsted, 1845

The number of species in this genus is very large and many

placed here in the past have since been removed to other genera.

1 have followed DSrjes (1968a) as to disposition of these.

Convoluta cinereus Graff, 1874 = Amphiscolops cinereus. Convoluta convoluta (Abildgaard, 1806). European Arctic and Atlantic coasts, North Sea, Canary Islands, Mediterra- nean, Black Sea. On algae. Common.

Convoluta diploposthia Sleinbock, 1931 = Anaperus rubellus. Convoluta flavibacillum Jensen, 1878 = Conaperta flavi- bacillum. Convoluta groenlandica Levinsen, 1879 = Childia groenlandica. Convoluta helgolandica DOrjes, 1968. North Sea. In fine sand. Convoluta karlingi Westblad, 1946 = Philocelis karlingi. Convoluta langerhansi Graff, 1882 = Amphiscolops langerhansi. Convoluta lutheri Westblad, 1946 = Pelophila lutheri. Convoluta macroposthia Steinbock, 1931 = Paraphanostoma

macroposthium.

Convoluta norwegica "WesMad, 1946 = Conaperta norwegica.

Convoluta parado.xa Orsted, 1845 = Convoluta convoluta. Convoluta pusilla Westblad, 1946 = Philaclinoposthia pusilla. Convoluta rhammifera Westblad, 1946 = Philactinoposthia

rhammifera.

Convoluta roscoffensis Graff, 1904. Dorjes (1968a) says this is

*Polychoerus caudatus Mark, 1892. Formerly common from

New Jersey to Maine (Verrill 1892). Now rare but has been

collected on empty scallop shells (1-2 m) in Great Bay near Wauwinet, Mass., and once in bottom sand sample (5 m) at Menemsha, Mass. This beautiful orange species has been used

at Woods Hole in experimental studies (Child 1907; Keil

1929).

Genus Postaphanostoma Dorjes, 1%8

Postaphanostoma atriomagnum Dorjes, 1968. North

Sea. In sand without mud or detritus, 3-18 m. Postaphanostoma /Hum D'OTJes, 1968. North Sea. Common

interstitial form in various sands, 7-18 m. Postaphanostoma glandulosum Dorjes, 1968. North Sea. From gravel deposits.

Genus Praeaphanostoma Db'rjes, 1968

Praeaphanostoma brevifrons Db'rjes, 1968. North Sea. From very fine sand, 5 m. Praeaphanostoma chaetocaudatum DOrjes, 1968. North Sea. From coarse sand in shallow water. Praeaphanostoma longum DOrjes, 1968. North Sea. In fine sand, 6 m.

Praeaphanostoma lutheri (Westblad, 1946) = Pelophila lutheri Praeaphanostoma ruhrum Dorjes, 1968. North Sea. In fine sand, 5 m.

59
Genus Praeconvoluta Dorjes, 1968

Praeconvoluta karinae Dorjes, 1968. North Sea. In gravel

and rock pools, 1-2 m.

Praeconvoluta minor Faubel, 1974. North sea. From beach

sand. Praeconvoluta schmidti Faube\, \977. Norway. From beach

sand.

Genus Proaphanostoma Dorjes, 1972

Proaphanostoma tenuissima (Westblad, 1946). North Sea. 30 m. Proaphanostoma viridis An der Lan, 1936 = Haploposthia

viridis.

Genus Proconvoluta Dorjes, 1968

Proconvoluta primitiva Dorjes, 1968. North Sea. From

detritus zone in shallow water.

Genus Pseudaphanostoma Westblad, 1946

Pseudaphonostoma brevicaudatum Dorjes, 1968. North Sea

In muddy sand, shallow water. Pseudaphanostoma pelophilum Dorjes, 1968. North Sea.

In muddy sand, often with Zostera or Mytilus.

Pseudaphanostoma psammophilum Dorjes, 1968. North Sea

In sand of the swash zone and sublittorally in unstable sand areas. Pseudaphanostoma variabilis Westblad, 1946. North Sea. From clay with sand, 10-20 m.

Genus Pseudoposthia Westblad, 1946

Pseudoposthia macrogonopora Westblad, 1946. North Sea. From clay with sand.

FaraUy NEMERTODERMATIDAE Steinbock, 1930

See under Order NEMERTODERMATIDA at end.

FamUy DIOPISTHOPORIDAE Westblad, 1940

Genus Diopisthoporus Westblad, 1940

Diopisthoporus brachypharyngeus Dorjes, 1968. North Sea From fine sand, 5-8 m.

Diopisthoporus longitubus Westblad, 1940. North Sea,

Adriatic. From soft bottom to 360 m.

Diopisthoporus psammophilus Dorjes, 1968. North Sea. From fine sand, 5 m.

FamUy HALLANGIIDAE Westblad, 1948

Genus Hallangia Westblad, 1946

Hallangia proporoides Westblad, 1946. European Atlantic. From soft bottom to 100 m.

FamUy HAPLOPOSTHIIDAE Westblad, 1948

Genus Adenocauda Dorjes, 1%8

Adenocauda helgolandica Dorjes 1968. North Sea. In fine sand, 5 m.

Genus Afronta Hyman, 1944

*Afronta aurantiaca Hymdin, \9A\. Maine coast. Dredged in surface mud, 30 ft. Afronta rubra Faubel, 1976. North Sea. From surf zone.

Genus Haplogonaria Dorjes, 1%8

Haplogonaria elegans Faubel, 1916. North Sea. From sandy

shallows. Haplogonaria glandulifera Dorjes, 1968. North Sea. In fine sand, 5 m. Haplogonaria macrobursalia Dorjes, 1968. North Sea. Surface layers of coarse sediments, 2-6 m.

Haplogonaria minima (Westblad, 1946). North Sea, Mediter- ranean. From soft bottom, 16-150 m.

Haplogonaria psammalia Faubd, 197A. North Sea. In beach

sand. Haplogonaria simplex Dorjes, 1968. North Sea. From

coarse sand, 32 m. Haplogonaria sinubursalia Dorjes, 1968. North Sea. From fine sand, 5-8 m.

Haplogonaria syltensis Dorjes, 1968. North Sea. From

various sands to 15 m.

Haplogonaria viridis Dorjes, 1968. North Sea. From sandy

mud, 5-8 m.

Genus Haploposthia An der Lan, 1936

Haploposthia brunea An der Lan, 1936. Greenland. From

muddy bottoms, to 180 m.

Haploposthia monogonophora VJesMad, 1946 = Kuma monogonophora.

Haploposthia rubra (An der Lan, 1936). North Sea, Greenland, Adriatic. From soft bottom to 180 m.

Haploposthia rubropunctata Westblad, 1945. North Sea,

Adriatic. To 100 m.

Haploposthia viridis (An der Lan, 1936) = Kuma viridis.

Genus Kuma Marcus, 1950

Kuma monogonophora (Westblad, 1946). North Sea. 30- 40 m. Kuma viridis (An der Lan, 1936). Greenland, North Sea,

Adriatic. From soft bottom, 30-250 m.

Genus Parahaplogonaria Dorjes, 1968

Parahaplogonaria maxima Dorjes, 1968. North Sea. From

clay-mud in deep channel, 42 m.

Genus Parahaploposthia Dorjes, 1968

Parahaploposthia avesicula Dories, \96S. North Sea. In fine sand, 5 m.

60
Parahaploposthia brunea Faubel, 1976. North Sea. From

sublittoral coarse sand. Parahaploposthia cerebroepithelialaDoTjes, 1%8. North Sea. From sand and muddy sand, 5-8 m.

Genus Pseudohaplogonaria Dorjes, 1%8

Pseudohaplogonaria stytifera (Westblad, 1946) = Philacli- noposlhia stylifera. Pseudohaplogonaria sutcliffei (Hanson, 1961). Bermuda.

On seaweeds and sargassum. Pseudohaplogonaria vacua Dorjes, 1968. North Sea. In fine gravel and mud.

Pseudohaplogonaria viridipunctata (Westblad, 1946). North

Sea, Mediterranean, Adriatic. From soft bottoms, 5-40 m.

Genus Simplicomorpha Dorjes, 1968

Simplicomorpha gigantorhabditis Dorjes, 1968. North Sea.

In coarse sand below swash zone.

FamUy OTOCELIDIDAE Westblad, 1948

Genus Archocelis Dorjes, 1968

Archocelis macrorhabditis Dorjes, 1968. North Sea. On

shells and mud, 5 m.

Genus Haplotestis Dorjes, 1968

Haplotestis curvitubus Dorjes, 1968. North Sea. From

coarse sand, 32 m.

Genus Notocelis Dorjes, 1968

Notocelis gullmarensis (Westblad, 1946). North Sea, Mediterranean. From coarse gravel with shells, shallow water.

Genus Otocelis Diesing, 1862

Otocelis rubropunctata (O. Schmidt, 1852). Mediterranean,

Black Sea. Northern records of this are a separate species, Otocelis westbladi, according to Ax (1959). In detritus-rich

fine sand.

Otocelis westbladi Ax, 1959. North Sea. From mud, 5-20 m.

Genus Philocelis Dorjes, 1968

Philocelis cellata DOrjes, 1968. North Sea. From detritus- rich sand, 2-6 m.

Philocelis karlingi (Westblad, 1946). North Sea, Baltic. In course sand, 2-6 m.

FamUy HOFSTENIIDAE Bock, 1923

Genus Hofstenia Bock, 1923

Hofstenia giselae Steinbock, 1966. Bimini. On Thalassia. Hofstenia miami Correa, 1960. Florida and Curacao. On

algae.

FamUy PARATOMELLIDAE Dorjes, 1%8

Genus Hesiolicium Crezee and Tyler, 1976

Hesiolicium inops Crezee and Tyler, 1976. New River, N.C.

In seawater.

Genus Paratomella Dorjes, 1966

*Paratoinella rubra Rieger and Ott, 1971. North Carolina, Mediterranean. In clean sand in shallow water. Paratomella unichaeta DoTjes, 1966. North Sea. Clean sand and gravel, 3-5 m.

FamUy NADINIDAE Dorjes, 1%8

One genus and one species only. Genus Nadina^ Uljanin,

1870. Mediterranean.

FamUy ANAPERIDAE Dorjes. 1968

Genus Achoerus Beklemischev, 1914

Achoerus pachycaudatus Dories, \96S. North Sea. Shallow

water, soft bottom.

Genus Anaperus Graff, 1911

Anaperus balticus Meixner, 1938 = Anaperus tvaerminnensis. *Anaperus gardineri Graff, 1911. Woods Hole, Mass.

Sandy mud or mud, subtidal. Anaperus rubellus Westblad, 1945. North Atlantic, Mediterranean. From soft bottom, 15-100 m. Anaperus tvaerminnensis (Luther, 1912). North Sea to

Iceland. From sand and mud to 36 m.

Genus Palmenia Luther, 1912

Palmenia baltica Meixner, 1938 = Anaperus tvaerminnensis. Palmenia tvaerminnensis Luther, 1912 = Anaperus tvaerminnensis.

Genus Palmeniola Forsius, 1925

Palmeniola baltica Meixner, 1938 = Anaperus tvaerminnensis. Palmeniola tvaerminnensis FoTsius, 1925 = Anaperus tvaerminnensis.

Genus Paranaperus Westblad, 1942

Paranaperus pellucidus Westblad, 1942. North Sea, Adriatic. From soft bottom, 20-150 m.

Genus Philachoerus Dorjes, 1968

Philachoerus johanni Dorjes, 1968. North Sea. On surface of mud.

^Myosromella Ried!. 1954, is a synonym of this genus.

61
Family ANTIGONARIIDAE Dorjes, 1%8

Geaus Aniigonaria Dorjes, 1%8

Antigonaria arenaria Dorjes, 1968. North Sea. From fine sand, 5 m.

FamUy CHILDIIDAE Dorjes, 1968

Genus Actinoposthia An der Lan, 1936

Actinoposthia biaculeata Faubel, 1974. North Sea. From

coarse sand in swash zone, 6-9 m.

Actinoposthia caudata An der Lan, 1936. Greenland. 180- 300 m.

Actinoposthia haplovata Dorjes, 1968. North Sea. From

fine sand, 5 m.

Actinoposthia tonga Faubel, 1976. North Sea. In beach

sand. Actinoposthia pigmentea Faubel, 1976. North Sea. From

sandy shallows or in sand to 10 cm.

Genus Adeloposthia An der Lan, 1936

One species A . elegans = Parapropors elegans. An der Lan

listed this as a species of "uncertain position" and Dorjes

(1968a) moved it into Paraproporus.

Geaus Archactinoposthia Dorjes, 1968*

Archactinoposthia pelophila D'oTJes, 196&. North Sea. Clay

and sand, 5 m.

Genus Atriofronta Dorjes, 1968

Atriofronta polyvacuola Dorjes, 1968. Fine to coarse sand, to

5 m.

Genus ChUdia, 1910

Childia baltica Luther, 1912 = Childia groenlandica.

*Childia groenlandica (Levinson, 1879). North Atlantic,

South Atlantic (Brazil), East and West coasts of the United

States, Mediterranean. Mud, algae, plankton, to 80 m.

Childia pansa Marcus, 1950 = Childia groenlandica.

*Childia spinosa Graff, 1911 = Childia groenlandica.

Genus Microposthia Faubel, 1974

Microposthia listensis Faubel, 1974. North Sea. In sandy

beach.

Genus Paraphanostoma Steinbock, 1931

Paraphanostoma brachyposthium Westblad, 1942. North

Sea. Common in dredge hauls. From muddy bottom, to 360 m.

Paraphanostoma crassum Westblad, 1942. North Sea, Adriatic. From soft bottom, 10-130 m. Paraphanostoma cycloposthium Westblad, 1942. North Sea,

Adriatic. From soft bottom, to 250 m. Paraphanostoma dubium Westblad, 1942. North Sea to Ice- land, Adriatic. From clay, 30-700 m. Paraphanostoma gracilis Westblad, 1945. North Sea. From

clay and sand, 5-60 m. Paraphanostoma macroposthium Steinbock, 1931. North

Atlantic to Iceland, Adriatic. Mostly from soft bottom,

to 22 m. Paraphanostoma submaculatum Westblad, 1942. North Sea,

Adriatic. From soft bottom, 5-180 m. Paraphanostoma trianguliferm Westblad, 1942. North Sea. From mud, sand, and shell gravel, 25-400 m.

Genus Paraproporus Westblad, 1945

Paraproporus diovatus Dorjes, 1968. North Sea. In fine mud.

Paraproporus elegans (An der Lan, 1936). Greenland,

Iceland. Paraproporus rosettiformis Faubel, 1974. North Sea. In medium to fine sand in shallow water. Paraproporus rubescens Westblad, 1945. North Sea, Adriatic. From mud, 5-20 m.

Genus PelophUa Dorjes, 1968

Pelophila cavernosa Dorjes, 1968 = Pelophila lutheri. Pelophila lutheri (Westblad, 1946). North Sea to Iceland, Mediterranean. From clay or mud, to 120 m.

Pelophyla pachymorpha Dorjes, \968. North Sea. In coarse

gravel.

Genus Philactinoposthia Dorjes, 1968

Philactinoposthia adenogonaria Dorjes, 1968. North Sea. From mud, 8 m.

Philactinoposthia diploposthia Dorjes, 1968. North Sea. Fine sand with some detritus, 5 m.

Philactinoposthia helgolandica Dorjes, 1968. North Sea. From coarse sand, 33 m.

Philactinoposthia pusilla (Westblad, 1946). North Sea. From sand and clay, 10-20 m.

Philactinoposthia rhammifera (Westblad, 1946). North Sea to

Iceland. Occurs sporadically, 15-20 m. Philactinoposthia saliens (Graff, 1882). North Sea,

Mediterranean. From sand and mud, mostly shallow water. Philactinoposthia stylifera (Westblad, 1946). North Sea. From clay with sand, 10-20 m.

Philactinoposthia viridis Dorjes, 1968. North Sea. From

growth on an old shipwreck.

Philactinoposthia viridorhabditis Dorjes, 1968. North Sea. From fine sand.

^In his key and definition of genera, Dorjes {1968a) lists a genus Proactinoposthia and a species Proaclmoposrhia pelophila, but description of a species Archactinoposthia pelophila

is placed in position for this genus (p. 335) and it is so listed in Dorjes' (1968b) article on the ecology of the acoels.

Genus Proactinoposthia Dorjes, 1968

Proactinoposthia pelophila Dorjes, 1968 = Archactinoposthia

pelophila.

62
Genus Pseudactinoposlhia Dorjes, 1968 Genus Postmecynostomum Dorjes, 1968

Pseudaclinoposthia granaria Dories, \96&. North Sea. From

fine sand, 8 m.

Pseudactinoposthia saltans Dorjes, 1968. North Sea. In growth on side of a boat.

Genus Tetraposthia An der Lan, 1936

Tetraposthia colymbetis An der Lan, 1936. Greenland.

Poorly known.

FamUy MECYNOSTOMIDAE Dorjes, 1%8

Genus Mecynostomum Van Beneden, 1870

Mecynoslomum agile Jensen, 1878 = Archaphanostoma agile. Mecynostomum auritum (Schultze, 1851). North Sea,

Mediterranean, Black Sea, salt spring in Germany. From

sand and mud in shallow water. Past records of this species

may actually involve the following: 1) M. auritum without a bursa and 2) these species with a bursa: M. auritum forma

typica changed to Pseudmecynostomum westbladi Dorjes

1968; M. auritum forma flavescens changed to Pseudmecynostomum flavescens (Westblad 1946); and M.

auritum forma glandulosum changed to Postmecynostomum

glandulosum (Westblad 1946) (see Dorjes 1968a:l 16; Dorjes

and Karling 1975:181). Mecynostomum bathycolum Westblad, 1948 = Pseudmecynostomum bathycolum.

Mecynostomum haplovarium Do'rjes, 1968. North

Sea. From detritus-rich or muddy sand, shallow water. Mecynostomum lutheri (Westblad, 1946) = Pelophila lutheri. Mecynostomum macrobursalis (Westblad, 1946) = Pseudmecynostomum macrobursalium.

Mecynostomum macrospiriferum (Westblad, 1946) = Archaphanostoma macrospiriferum.

Mecynostomum minimum Westblad, 1946 = Haplogonaria

minima.

Mecynostomum predatum Faubel, 1976. North Sea. In beach sand. Mecynostomum tenuissimum Westblad, 1946 = Proaphano- stoma tenuissima.

Genus Paedomecynostomum Dorjes, 1%8

Paedomecynostomum bruneum Dorjes, 1968. North Sea. From sand with detritus, or muddy sand, shallow water to 10 m.

Genus Paramecynostomum Dorjes, 1968

*Paramecynostomum diversicolor (Orsted, 1845). North

Atlantic, Mediterranean, Black Sea, Massachusetts, Rhode

Island. Algae, mud, and sand in shallow water.

Genus Philomecynostomum Dorjes, 1968

Philomecynostomum lapillum Dorjes, 1968. North Sea.

Detritus-rich sand, shallow water.

Postmecynostomum glandulosum (Westblad, 1946). North

Sea. From sand with mud, 5-20 m. Postmecynostomum pictum Dorjes, 1968. North Sea. On

mud or algae in Mytilus colonies, to 5 m.

Genus Pseudmecynostomum Dorjes, 1968

Pseudmecynostomum bathycolum (Westblad, 1948). North

Sea. From soft bottom, 70-90 m. Pseudmecynostomum boreale Faubel, 1977. North Sea. From detritus-rich, muddy sand. Pseudmecynostomum bruneofilum Faubel, 1974. North Sea.

In shallow water in sand down to 10 cm. Pseudmecynostomum bruneum Dorjes, 1%8. North Sea. Mixed sand, gravel, mud.

Pseudmecynostomum flavescens Dorjes, 1968. North Sea. From sand and muddy sand, to 30 m. Pseudmecynostomum fragilis Dorjes, 1968. North Sea. From fine sand, 5-8 m. Pseudmecynostomum granulum Dorjes, 1968. North Sea. Dredged, on algae.

Pseudmecynostomum juistensis Dorjes, 1968. North Sea. On mud, intertidal. Pseudmecynostomum macrobursalium (Westblad, 1946).

North Sea. From clay, 25-35 m. Pseudmecynostomum maritimum Dorjes, 1968. North Sea. From coarse gravel, 8 m. Pseudmecynostomum papillosum Faubel, 1974. North Sea. Shallow sand area. Pseudmecynostomum pelophilum Dorjes, 1968. North Sea.

Salt meadow ditch on mud.

Pseudmecynostomum westbladi Dorjes, 1968. North Sea. From mud or sand, to 10 m.

FamUy SOLENOnLOMORPHIDAE Dorjes, 1968

Genus Endocincta Crezee, 1975

* Endocincta punctata Crezee, \915. North Carolina. In sand

flats.

Genus Fusantrum Crezee, 1975

*Fusantrum rhammiphorum Crezee, 1975. North Carohna.

In sand.

Genus Myopea Crezee, 1975

*Myopea crassula Crezee, 1975. North Carolina. In sandy

and muddy flats. * Myopea latafaucium Crezee, 1975. North Carolina. From

sand flats.

Genus OUgofilomorpha Dorjes, 1%8

Oligofilomorpha interstitiophilum Faubel, 1974. North Sea. From sand flats. Oligofilomorpha karlingi Dorjes, 1971. North Sea. From

muddy sand, 8 m.

63
Genus Solenofilomorpha Dorjes, 1%8

Solenofilomorpha longissima Dorjes, 1968. North Sea. From muddy sand, 5 m.

FamUy ANTROPOSTHIIDAE Faubel, 1976

Genus Adenopea Antonius, 1968

Adenopea illardatus (Lohner and Micoletzky, 1911). Pelagic

in Mediterranean.

Genus Antroposthia Faubel, 1974

Antroposthia axi Faubel, 1974. North Sea. In coarse sand. Antroposthia iinipora Faubel, 1974. North Sea. In beach

sand.

Genus Convoluella Faubel, 1974

Convoluella brunea Faubel, 1974. North Sea. In shallow water to 10 cm in sand.

Genus Unantra Faubel, 1976

Unantrapolyvacuola Faubel, 1916. North Sea. In sublittoral coarse sand.

Order NEMERTODERMATIDA Karling, 1940

FamUy NEMERTODERMATIDAE Steinbock, 1930

Genus Flagellophora Faubel and Dorjes, 1978

Flagellophora apelti Faubel and Dorjes, 1978. North Sea. From coarse sand and shell gravel, sublittoral.

Genus Meara Westblad, 1949

Meara stichopi Westblad, 1949. North Sea. In intestine and body cavity of holothurians.

Genus Nemertoderma Steinbock, 1930

* Nemertoderma bathycola, Steinbock, 1930. North Atlantic

to Greenland, North Sea, Mediterranean; Buzzards Bay

and Vineyard Sound, Mass. Subtidal. Four geographic

varities of this species have been designated (Dorjes 1968; Riedl 1960). Variety in our area may be different. Nemertoderma rubra Faubel, \916. North Sea. From coarse

sand. Nemertoderma sp. A, B. D. Reported by Tyler and Rieger

(1977) from North Carolina.

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66
SYSTEMATIC INDEX

(Italic numbers are references to figures)

Achoerus 20, 61 pachycaudatus 19, 20, 6\

A ctinoposthia 38, 62

biaculeata 62 caudata i5, 58, 62

haplovata 22, 31, 38, dl

longa 37, 38,62

pigmentea 37, 38, 62 Adeloposihia 62

elegans 62 Adenocauda 27, 60

helgolandica 27, 60 Adenopea 29, 58, 64

illardatus 29, 64 Aechmalotus 16 pyrola 16 Afronta 28, 60

aurantiaca 25,60

rubra 2<S, 60

Amphichoerus 58 A mphiscolops 47, 58 bermudensis 47, 58 cinereus 47, 58, 59

evetinae 9

gardineri 58 langerhansi 4, 47, 58, 59

sargassi 9, 58

virescens 58 Anaperidae 19, 23, 61 Anaperus 21, 58, 61

ballicus 61 gardineri 27, 61 rubellus 59, 61 tvaerminnensis 19, 20, 6\

Antigonariidae 13, 62 Antigonaria 13, 62

arenaria 13.62

Antroposthiidae 1, 23, 58, 64

Antroposthia 30, 64

axi 64

unipora 50, 64 Aphanostomidae 1 Aphanostoma 50, 58 album 5/, 58 aurantiacum 58 auritum 58 caudatum 58 divaceum 58

diversicolor 58

elegans 58

lulheri 58 macrobursalis 58 macrospiriferum 58 minimum 58 olivaceum 58 rhomboides 58 rubropunctata 58 tenuissimum 58

virescens 58

A rchactinoposthia 41 ,62 pelophila 4/, 62 A rchaphanostoma 42, 58

agile 42, 58, 59, 63

histobursalium 42, 58 macrospiriferum 22, 31, 42, 5S, 59, 6^ A rchiproporus 10, 58 minimus 10, 70, 58 Archocelis 18, 61 macrorhabditis 17, 18, 61 Archoophora 1 A iriofronla 37, 62 polyvacuola 57, 62 A vagina 53, 59

aurita 59

glandulifera 59

incola 55, 59

sublitoralis 59

tenuissima 59

Baltalimania 55, 59

agile 59 macrospiriferum 59

kosswigi 55 Brachypea 45 kenoma 45 Bursosaphia 50, 59

baltalimaniaformis 42, 50, 59

Childiidae 35, 62

Childia 36, 62

baltica 62

groenlandica 56, 59, 62 pansa 62

spinosa 62 Conaperta 44, 59

flavibacillum 4, 59 norwegica 45, 44, 59

thela 44 variomorpha 59

Convoluella 30, 64

brunea 22.23,30,6^

Convolutidae 1, 35, 58 Convoluta 44, 59

cinereus 59 convoluta 45, 59

diploposthia 59

flavibacillum 59

groenlandica 59

helgolandica 59

karlingi 59

langerhansi 59

lulheri 59 macroposthia 59 norwegica 59 paradoxa 59

pusilla 59 rhammifera 59

roscoffensis 59

saliens 59

stylifera 59

67
sutcliffei 59 variomorpha 59

viridipunclata 59 Deuterogonaria 26 thauma 24,26

Diatomovara 47 amoena 47

Diopisthoporidae 10, 60

Diopisthoporus 10, 60 brachypharyngeus 60

longitubus 10,60

psammophilus 60

Endocincta 13, 63 punctata 13,63, Exocelis 17 exopenis 17

Faerlea 54, 59

echinocardii 59

fragilis 54,59

glomerata 59

Flagellophora 1 , 5, 56, 64

apeiti 56, 64 Fusantrum 13, 63 rhammiphorum 13, 67> HaUangiidae 14, 60

Hallangia 16, 60

proporoides 3, 7(5, 60

Haplocetis 18 dichone 18 Haplodiscus 43, 52, 59

bocki J5, 43

piger 9, 9, 52,59

weldoni 59 Haplogonaria 24, 60

elegans 2i, 60

glandulifera 24, 60

macrobursalia 25, 60

minima 2< 58, 60, 63 psammalia 60

simplex 22, 25, 60

sinubursalia 60

syltensis 60

viridis 60

Haploposthiidae 23, 60

Haploposthia 28, 60

albiventer 23 brunea 60 monogonophora 60

rubra /9. 22, 23, 29, 60

rubropunctata 29, 60

viridis 60

Haplotestis 19, 61 curvitubus 79, 61 Hesiolicium 14, 61 inops 4, 74, 61 Hofsteniidae 1, 14, 61 Hofstenia 15, 61

atroviridis 75

giselae 61 miami 61 Hofsteniola 15 pardii 75

Kuma 29, 60

albiventer 23, 29, 60

brevicauda 29

monogonophora 19, 23. 27,19, GD

viridis 60 Limnoposthia 34

polonica 1 , 54, 35 Marcusiola 15 linga 75 Meara 1, 5, 57, 64

stichopi 57, 64 Mecynostomidae 3 1 , 34, 63 Mecynostomum 32, 63

agile 63 auritum J2, 58, 59, 63

flavescens 63 glandulosum 63

typica 63 bathycolum 63 haplovarium 31, 32,63

lutheri 63 macrobursalis 63 macrospiriferum 63 minimum 63 predatum 63 tenuissimum 63 Microposthia 38, 62

lislensis 38,62

Monoposthia 39

pseudovesicula 39

Myopea 12, 63

crassula 72, 63 lalafaucium 63 Myostomella 61 Nadinidae 16, 61 Nadina 16, 61 pulchella 3, 75 Nemertodermatidae 1 , 60, 64 Nemertoderma 1 , 5, 57, 64

bathycola 5, 57, 64

rubra 5, 57, 64

sp. A, B,

D 64

Neochildia 54, 59 fusca 5, 54, 59

Notocelis 17, 61 gullmarensis 77, 61 Oligochoerus 3, 46

limnophilus 1 , 46 Oligofilomorpha 12, 63

interstitiophilum 77, 63

karlingi 72, 63 Opisthandropora-Abursalia 1 Otocelididae 16, 61

Otocelis 18,61

rubropunctata 18, 58, 61 westbladi 76, 61 Oxyposthia 55 praedator 55 Paedomecynostomum 33, 63 bruneum ii, 63 Palmenia 61

baltica 61 tvaerminnensis 61

68
Paimeniota 61

baliica 61 ivaerminnensis 61 Parahaplogonaria 25, 60 maxima 23,24,25,60

Parahaploposthia 28, 60

avesicula 22, 27, 28, 60 brunea 61

cerebroepitheliata 2<S, 61 Paramecynostomum 34, 58, 63

diversicolor 33, 34, 5S,6'i Paranaperus 19, 20, 61

pellucidus 20, 23, 61 Paraphanosloma 40, 62

brachyposiliium 62 crassum 62 cydoposlhium 62 dubium 62

gracilis 40, 62 macroposthium 35, 40, 59,62

submaculatum 62

trianguliferum 62 Paraproporus 36, 62

diovatus 35, 37,62

elegans 62

rosettiformis 62

rubescens i6, 62

Paratomellidae 13,61 Paratometla 14, 61 rubra 14, 6\ unichaeta A,14,6\

Parotocelis 18 luleopunctata 19

Pelophila 41 , 62

cavernosa 41, 62

lutheri 58, 59, 62, 63 pachymorpha 41,62

Philachoerus 21,61

johanni 20, 21, 61 Philactinoposthia 39, 62 adenogonaria iP, 62

diploposthia 62

helgolandica 62

pusilla 59, 62 rhammifera 59, 62

saliens 59, 59, 62

stylifera 59, 61, 62

viridis 62

viridorhabditis 62

Philocelis 18, 61

cellata 17, 6\

karlingi 59, 61 Philomecynostomum 33, 63

lapillum 33, 6'i Polychoerus 45, 46, 59 caudatus 3,6,46,59

Postaphanostoma 49, 59 airiomagnum 43, 49, 59

filum 48,49,59

glandulosum 59 Postmecynostomum 34, 63 glandulosum 63 pictum 33, 34,61)

Praeaphanosloma 50, 59

brevifrons 59 chaelocaudalum 50, 59 longum 59

lutheri 50, 59 rubrum 59 Praeconvoluta 49, 60

karinae 48,49,60

minor 60

schmidti 60

Proactinoposihia 62

pelophila 62 Proandropora-Abursalia 1 Proandropora-Bursalia 1 Proaphanostoma 5 1 , 59, 60

tenuissima 4S, 5/, 58, 60, 63

viridis 60 Proconvoluta 5 1 , 60

primitiva 35, 51,60

Proporidae 1, 10, 58 Proporus 10, 58

brochii 58

lonchitis 58 minimus 58 rubropunctatus 58 venenosus 10,5% venenosus 58

violaceus 58

viridiflavus 58 Pseudactinoposthia 40, 63 granaria 63

saltans -^0, 63 Pseudanaperus 20

tinclus 21 Pseudaphanostoma 56, 60 brevicaudatum 60 pelophilum 56, 60

psammophilum 35, 52, 56, 60

variabilis 56, 60 Pseudmecynostomum 32, 63 bathycolum 63

boreale 63 bruneofilum 63 bruneum 63 flavescens 63

fragilis 63 granulum 22, 63

juistensis 63 macrobursalium 58, 63 maritimum 32, 52, 63 papillosum 63 pelophilum 31, 32,63

westbladi 63 Pseudohaplogonaria 26, 61 macnaei 4

stylifera 24, 26, 61

sutcliffei 59, 61 vacua 25, 26, 61

viridipunctata 59, 61 Pseudokuma 25 orphinum 24, 25 Pseudoposthia 53, 60 macrogonopora 55, 60

69
Rimicola 53

glacialis 52, 53

Schizoporus 58 venenosus 58

Simplicomorpha 27, 61 gigantorhabditis 27, 61

Solenofilomorphidae 11 , 63 Solenofilomorpha 1 2, 64

longissima 12, (A

Tetraposthia 39, 63 colymheiis J9, 63 Unanlra 30, 64 polyvacuola 30,64

ACKNOWLEDGMENTS

Preparation of the "Marine Flora and Fauna of the Northeastern United States" is being coordinated by the following

Board:

Coordinating Editor: Melbourne R. Carriker, College of Marine Studies, University of Delaware, Lewes, DE 19958.

Editorial Advisers: Marie B. Abbott, 259 High Street, Coventry, CT 06238. Arthur G. Humes, Boston University Marine Program,

Marine Biological Laboratory, Woods Hole, MA 02543. Wesley N. Tiffney, Professor Emeritus, Boston University, 226 Edge Hill Road, Sharon, MA 02067. Ruth D. Turner, Museum of Comparative Zoology, Harvard

University, Cambridge, MA 02138. Roland L. Wigley, National Marine Fisheries Service, Northeast Fisheries Center, NOAA, Woods Hole, MA 02543.

Robert T. Wilce, Department of Botany, University of Massachusetts, Amherst, MA 02116.

The Board, which established the format for the "Marine

Flora and Fauna of the Northeastern United States," invites systematists to collaborate in the preparation of manuals,

reviews manuscripts, and advises the Scientific Editor of the National Marine Fisheries Service. Gratitude is expressed to Melbourne R. Carriker and to members of the Systematics-Ecology Program and the Marine

Biological Laboratory at Woods Hole, who provided assistance, laboratory space, and library facilities for the study of

Turbellaria. Drew University also provided funds, supplies, and

the use of a small laboratory on the campus. Suggestions and

critical reviews by a number of persons have been very helpful

and are acknowledged here with gratitude. Grace Beach, Eva

Montiero, and Susan Wier were most patient in typing and

proofreading the manuscript.

70
COORDINATING EDITOR'S COMMENTS

Publication of the "Marine Flora and Fauna of the Northeastern United States" is most timely in view of the growing

universal emphasis on environmental work and the urgent need

for more precise and complete identification of coastal organisms than has been available. It is mandatory, where possible, that organisms be identified accurately to species. Accurate

scientific names unlock the great quantities of biological infor- mation stored in libraries, obviate duplication of research already done, and often make possible prediction of attributes of organisms that have been inadequately studied. Louise Bush has degrees in Zoology and Entomology and was

teaching Invertebrate Zoology at Drew University when an NSF

Science Faculty Fellowship and a sabbatical leave from Drew

University provided her a year of study in marine biology in Florida and at Woods Hole, Mass. Her interest in Turbellaria began at this time and has continued with summer work at the Marine Biological Laboratory and at the Cornell University of New Hampshire Marine Laboratory on Appledore Island, Maine. Professor Emeritus of Zoology at Drew, she continues

her work with Turbellaria and serves as assistant curator in the George M. Gray Museum at the Marine Biological Laboratory

in Woods Hole.

Preparation of this manual was supported in part by a grant

from the Environmental Protection Agency to the Editorial

Board of the "Marine Flora and Fauna of the Northeastern United States!' Work on the "Marine Flora and Fauna of the Northeastern United States" by the Coordinating Editor is sup- ported by the College of Marine Studies, University of

Delaware.

Manuals are available from the following:

Superintendent of Documents, U.S. Government Printing

Office, Washington, D.C. 20402. User Service Branch, Library and Information Services, Division D822, Washington Science Center, Building H,

Rockville, MD 20852, at no charge as long as the supply

lasts. National Technical Information Services, U.S. Department

of Commerece, 5285 Port Royal Road, Springfield, VA

22161, either as paper copy or microfiche, for a charge.

Manuals are not copyrighted and so may be photocopied

from the NOAA Technical Report NMFS Circulars available in most major Hbraries. The manuals so far published in the NOAA Technical Report

NMFS Circular Series are listed below by author, title, Circular number, and NTIS accession number.

MARINE FLORA AND FAUNA OF THE NORTHEASTERN UNITED STATES:

COOK, DAVID C, and RALPH O. BRINKHURST. Annelida: Oligochaeta.

BORROR, ARTHUR C. Protozoa: Ciliophora

MOUL, EDWIN T. Higher Plants of the Marine Fringe.

McCLOSKEY, LAWRENCE R. Pycnogonida.

MANNING, RAYMOND B. Crustacea: Stomatopoda.

WILLIAMS, AUSTIN B. Crustacea: Decapoda.

POLLOCK, LELAND W. Tardigrada.

LARSON, RONALD J. Cnidaria: Scyphozoa.

CAVALIERE, A. R. Higher Fungi: Ascomycetes, Deuteromycetes, and Basidiomycetes.

COULL, BRUCE C. Copepoda: Harpacticoida.

CUTLER, EDWARD B. Sipuncula.

PAWSON, DAVID L. Echinodermata: Holothuroidea. HO, JU-SHEY. Copepoda: Lernaeopodidae and Sphyriidae.

HO, JU-SHEY. Copepoda: Cyclopoids Parasitic on Fishes. CRESSEY, ROGER F. Crustacea: Branchiura. BOVEE, EUGENE C, and THOMAS K. SAWYER. Protozoa: Sarcodina: Amoebae.

WATLING, LES. Crustacea: Cumacea. ZULLO,VICTOR A. Arthropoda: Cirripedia.

Circular

NOAA TECHNICAL REPORTS

NMFS Circular and Special Scientific Report—Fisheries

Guidelines for Contributors

CONTENTS OF MANUSCRIPT

First page. Give the title (as concise as possible) of the

paper and the author's name, and footnote the author's

affiliation, mailing address, and ZIP code.

Contents. Contains the text headings and abbreviated

figure legends and table headings. Dots should follow each

entry and page numbers should be omitted.

Abstract. Not to exceed one double-spaced page. Footnotes and literature citations do not belong in the abstract.

Text. See also Form of the Manuscript below. Follow the

U.S. Government Printing Office Style Manual, 1973 edition. Fish names, follow the American Fisheries Society

Special Publication No. 6, A List of Common and Scientific Names of Fishes from the United States and Canada, third

edition, 1970. Use short, brief, informative headings in place

of "Materials and Methods!'

Text footnotes. Type on a separate sheet from the text. For

unpublished or some processed material, give author, year,

title of manuscript, number of pages, and where it is filed

agency and its location.

Personal communications. Cite name in text and footnote.

Cite in footnote: John J. Jones, Fishery Biologist, Scripps

Institution of Oceanography, La Jolla, CA 92037, pers. commun. 21 May 1977.

Literature cited. In text as: Smith and Jones (1977) or (Smith and Jones 1977); if more than one author, list according to years (e.g.. Smith 1936; Jones et al. 1975; Doe 1977).

All papers referred to in the text should be listed alphabetically by the senior author's surname under the heading

"Literature Cited"; only the author's surname and initials

are required in the author line. The author is responsible for

the accuracy of the literature citations. Abbreviations of names of periodicals and serials should conform to Biological Abstracts List of Serials with Title Abbreviations. For- mat, see recent SSRF or Circular.

Abbreviations and symbols. Common ones, such as mm,

m, g, ml, mg, "C (for Celsius), %. %o, etc., should be used. Abbreviate units of measures only when used with numerals;

periods are rarely used in these abbreviations. But periods

are used in et al., vs., e.g., i.e.. Wash. (WA is used only with ZIP code), etc. Abbreviations are acceptable in tables and

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Measurements. Should be given in metric units. Other

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FORM OF THE MANUSCRIPT

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The sequence of the material should be:

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FIRST PAGE

CONTENTS

ABSTRACT

TEXT

LITERATURE CITED

TEXT FOOTNOTES

APPENDIX

TABLES (provide headings, including "Table" and Arabic

numeral, e.g.. Table I.-, Table 2.-, etc.) LIST OF FIGURE LEGENDS (entire legend, including

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ADDITIONAL INFORMATION

Send ribbon copy and two duplicated copies of the manuscript to:

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MBL WHOl Llbrai

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