Cheilostome Bryozoa of 

Late Eocene Aee From 

Eua, Tonga

GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E
Cheilostome Bryozoa of 

Late Eocene Age From 

Eua, Tonga

By ALAN H. CHEETHAM

LATE EOCENE FOSSILS FROM EUA, TONGA

GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E

Mixed assemblage of shallow- and deep-sea species 

from offreef tuffaceous limestone

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1972
UNITED STATES DEPARTMENT OF THE INTERIOR 

ROGERS C. B. MORTON, Secretary

GEOLOGICAL SURVEY 

W. A. Radlinski, Acting Director

Library of Congress catalog-card No. 70-181826

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 - Price 70 cents (paper cover)

Stock Number 2401-1203
LATE EOCENE FOSSILS FROM EUA, TONGA FOREWORD

One of the most widespread units of the Cenozoic 

section in the islands of the open Pacific is a series of 

limestones assigned to the upper Eocene (Tertiary 6). 

Such limestones, containing diagnostic larger Foraminifera, have been reported in many parts of an area 

spreading 4,000 miles across the tropical Pacific (fig. 1), 

from Palau and the Mariana Islands on the northwest 

through the Marshall Islands (Eniwetok) to Fiji and 

Tonga on the southeast (Whipple, in Hoffmeister, 1932, 

p. 79-86;Asano, 1939; Cole, 1950, 1957a, 1957b, 1960). 

In almost all the islands the limestones are dense and 

crystalline. Foraminifera and algae are abundant locally, but in most places fossils cannot be extracted and 

must therefore be studied in random thin sections. On 

the little island of Eua, Tonga, a locality was recently 

found where the Eocene limestone is tuffaceous, considerably weathered, and richly fossiliferous. Abundant 

fossils that represent a dozen organic groups were found. 

Such abundance and diversity signaled the find as a 

remarkable one that would add greatly to our knowledge of life in the western Pacific during the Eocene.

The island of Eua measures only 12 by 5 miles but 

it rises 1,000 feet above sea level. It occupies an interesting position tectonically, as its steep eastern side 

faces the Tonga Trench. In addition, Eua is the oldest 

island in the Tonga group that has a plutonic core 

(Guest, 1959) and a series of associated volcanic rocks, 

which are partly blanketed by thick limestones of late 

Eocene age. Younger volcanic rocks and sediments of 

late Tertiary age are also present (Hoffmeister, 1932).

This series of reports is concerned with one facies of 

the upper Eocene limestone. After the limestone series 

was deposited, Eua was uplifted periodically and a 

sequence of six terraces was cut in the limestones on 

the windward (eastern) side. Hoffmeister was the 

first to recognize the Eocene age of the main limestone 

of the terraces, three of which have veneers of Pliocene 

reef corals. He made a planetable map of the terraced 

eastern ridge and recorded the average altitudes of the 

terraces as 100, 200, 340, 400, 550, and 760 feet. The 

east-facing "rocky backbone" of Eua thus looks in 

profile like a giant staircase facing the Tonga Trench. 

The Eocene limestone may once have covered all of Eua

but is now largely limited to the eastern ridge (Hoffmeister, 1932; the Eocene Foraminifera were described by Whipple in this same report, p. 79-86).

The fossils described in this series of reports were 

obtained from an outcrop 011 the 400-foot terrace 

about a quarter of a mile north of Vaingana (fig. 2). 

At this locality, the limestone lies close to the underlying volcanic rock and is tuffaceous and prrtly 

weathered; almost everywhere else on Eua the limestone 

is pure, hard, and crystalline.

In 1943, Harold T. Stearns, then of the U.S. Geological Survey, also served as a consultant to the 

Armed Forces at Pacific bases and made a brief 

visit to Eua. He collected a sample that contained 

half a dozen fossil brachiopods from the 400-foot 

terrace on the eastern side of the island. Steam? recorded the locality as: "Tele-a-hiva at elevation 

of 400 feet about % mile north of army lookout tower, 

at the second stream north of Vaigana [sic]." The 

brachiopods were examined by G. A. Cooper of the 

U.S. National Museum. Some years later when I 

was studying other island fossils collected by Stearns, 

Cooper showed me the brachiopods and expressed 

a desire for additional specimens so that he could 

continue his study of their internal structures.

In 1966,1 learned that Yoshio Kondo of the Bemice 

P. Bishop Museum in Honolulu intended to visit Eua in 

connection with his studies of living Pacific island land 

snails (under National Science Foundation grant 

GB-3974). I sent Stearns' locality data and marked 

copy of Hoffmeister's Eua map to Kondo, and I informed Stearns of the plan to collect additional 

material.

Late in August 1967, Kondo reached Eua and, aided 

by a Tongan guide, Tomiki, and an interpreter, Mosese 

Vea, spent 2 days searching for the fossil locality. The 

lookout tower mentioned by Stearns 110 longer exists 

and Kondo found that Tele-a-hiva translates to "Nine 

Gulches." Traveling northward from "Vaigana" (Otu 

Vaingana) through heavy brush on exceedingly rugged 

karst topography for about 1,000 feet, he reached the 

first of the gulches. There he found a soft fossiliferous 

layer between two harder limestones and collected a

in

440-746 O - 71 -
40-pound sample of the material. This gulch locality 

is probably not the exact spot visited by Stearns. The 

two collections have minor differences in nature of 

preservation, but they obviously came from the same 

formation.

In 1969 Wilfred Bryan of the Carnegie Institution 

of Washington collected additional material from the 

locality sampled by Kondo. Bryan's material was 

taken from soft calcareous- tuffs 2-3 feet in thickness 

that dipped 30-40 E. These calcareous tuffs were

fer-'AM FUI l;JM^

FIGURE 1. Location of Tonga and other island groups in the southwest Pacific where upper Eocene limestone has been identified. Dashed line marks structural boundary of the Pacific Basin (andesite line). Islands shown include the surrounding reefs.

IV
directly underlain by several feet of harder fossiliferous material that, in turn, lay above agglomerate 

with truncated dikes. The horizon sampled was at an 

altitude of about 355 feet in a gully notched into the 

400-foot terrace.

The exact extent of the richly fossiliferous bed is 

not known. In 1926, when Hoffmeister made his

175°55'W

21°20'S

21°25'S

FIGURE 2. Map of Eua, Tonga, showing the location of the 

recently discovered fossil outcrop (X) and the main mass 

of Eocene limestone (patterned area) on the east side of 

the island, as mapped by Hoffmeister (1932).

map of the terraces, he did not come upon this fades, 

and in 1928 when I spent 2 weeks on Eua with Hoffmeister, reviewing his mapping, no exposures of this 

zone were seen although we visited Vaingana. Additional fieldwork in the area of the rugged "Nine 

Gulches" would be worthwhile.

William Melson of the Smithsonian Institution 

examined hand specimens and thin sections of the 

tuffaceous limestone and noted that the volcanic constituents are highly altered, making it difficult to 

determine their original nature. The rock is composed of 50 percent or more of volcanoclastic debris, 

much of which has been replaced by calcite. The 

predominant volcanic fragments are of porphyritic 

pumiceous glassy material; most of the phenocrysts 

are plagioclase, now largely replaced by calcite. The 

original groundmass of pumiceous glass is row 

devitrified and dark brown. Fragments of tuff are 

rare. There appears to be a large and varied assemblage of secondary minerals. The volcanic fragments 

are mainly porphyritic andesitic rocks, or possibly 

plagioclase-bearing dacites. The presence of abundant fossils suggests that the volcanic material has 

been reworked.

The soft tuffaceous limestones collected on Fua 

were treated with a wetting agent and penetrant in 

the laboratory. The material broke down easily, revealing a variety of fossil remains: Foraminifera, 

discoasters, corals, hydrozoans, brachiopods, bryozoans, annelids, crinoids, echinoids, ostracodes, 

barnacles, decapod crustaceans, mollusks, shark 

teeth, otoliths, and spores and other plant microfossils.

W. Storrs Cole has described the larger Foraminifera ; these fossils suggest to him a depth of deposition of about 200 feet, but other groups notably the 

smaller Foraminifera, the corals, brachiopods, bryozoans, mollusks, ostracodes, and barnacles point to 

a considerably greater depth of deposition.

Material representing a total of 17 organic groups 

was distributed to paleontologists for study and report. Seven of these collections were small or were 

made up of incomplete specimens leading only to 

summary reports, but the others, except for the 

larger Foraminifera, contained much new material. 

The brachiopod, bryozoan, ostracode, barnacle, and 

mollusk collections contained the first identifiable 

Eocene species from the islands of the open Pacific, 

an area extending 4,000 miles from Palau to Torga.

HARRY S. LADO

CONTENTS

Foreword _ .

Abstract --_ . .

Introduction _ . .

Paleoenvironments .._ ....... . ..... . .

Distribution of Tetraplaria.. ............

Distribution of Bifaxaria.....................

Distribution of Tessaradoma...............

Tongan cheilostome faunal elementsMorphology of deep-water species. ......

Systematic paleontology ....... ....................

Chaperiidae ...- .-.- .... ...........-.

Patsyellal .......................................

Cellariidae ..... .-_--......--.-..--.--.-.............

Cellaria ...........................................

Bicellariellidae -- ....-.............................

Beania .............................................

Scrupocellariidae -..... ..... ...........

Canda _ . ___ _

Page

III 

El

1

2

2

4

6

6

7

Menipea ...

9

9

9

9

10

Page

Cribrilinidae ________________ - - E10

Figularial ...........

Exechonellidae 

Triporula ........ 

Bifaxariidae . .._ . 

Bifaxaria ._.. ... 

Spiroporinidae ..___.___

Spiroporina .... 

Tessaradoma .. 

Siphonicytaridae

Tubitrabecularia 

Sertellidae 

Reteporellina"! ... 

Schizoporellidae _________

Schizoporella .....

Chiastosellat ..... 

Tetraplariidae .... .

Tetraplaria .........

References cited __ __________-

Index __ ... ... 

10

11

11

11

11

14

14

15

16

16

17

17

17

17

18

18

18

22

25

ILLUSTRATIONS

[Plates follow index]

PLATE 1. Canda, Patsyellal, and Cellaria.

2. Figularial, Menipea, Beania, and Triporula.

3. Bifaxaria.

4. Bifaxaria, Chiastosella 1!, and Spiroporina.

5. Spiroporina, Schizoporella, and Tessaradoma.

6. Reteporellina'! and Tubitrabecularia.

7. Tetraplaria.

Pige

FIGURE 1. Map showing the location of Tonga and other island groups in the southwest Pacific where upper Eocene

limestone has been identified -.. .-...--. -... -. ..- .-. . . ._ - IV

2. Map of Eua, Tonga, showing the location of the recently discovered fossil outcrop and the main mass of

Eocene limestone ..-.............-- ---.... ._..-.--_..- ......................-..........--- --. -..------...---- -----.-------.---- - V

3. Map showing worldwide geographic and stratigraphic distribution of Tetraplaria ,................. .... .- ... E3

4. Graph showing depth-latitude distribution of living species of three genera of cheilostome Bryozoa represented in upper Eocene beds on Eua, Tonga. .. ...-. . . 4

5. Map showing worldwide geographic and stratigraphic distribution of Tessaradoma............. ..................... ... 5

6. Graph showing variations in width of successive pairs of autozooecia and distal kenozooecia in five internodes of Tetraplaria simata, n. sp... . . . _.. . 19

7. Graph showing variations in length of successive pairs of autozooecia and distal kenozooecia in five internodes of Tetraplaria simata, n. sp....... ................ ... . 20

TABLE

TABLE 1. Specimen abundance, other properties of cheilostome bryozoan species in two samples from upper Eocene beds

on Eua, Tonga ......... .......... ..... ............_ .... ........ . _. - E2

VII

LATE EOCENE FOSSILS FROM EUA, TONGA

CHEILOSTOME BRYOZOA OF LATE EOCENE AGE FROM EUA,

TONGA

By ALAN H. CHEETHAM

ABSTRACT

An assemblage of cheilostome Bryozoa from upper Eocene 

(Tertiary 6) beds on Eua, Tonga, appears to be a mixture of 

five autochthonous and 13 allochthonous species. The autochthonous element, which makes up about 85 percent of the 

specimens in the assemblage, includes the first known fossil 

cryophilic deep-sea cheilostomes. It can be inferred that these 

species have lived in water cooler than 13 °C at a depth that 

in the tropics or subtropics exceeded 200 meters. The much 

rarer but more diversified allochthonous element includes some 

thermophilic taxa that probably lived at depths less than 100 

meters in water having an average temperature of not much 

less than 20 °C in the coolest months. At least some of the 

allochthonous species grew attached to nonbouyant substrates 

and therefore must have been transported to the burial site 

from a shallow-bottom habitat.

In contrast to the allochthonous species, which show a variety of colony forms, all the inferred deep-water species had 

nonfenestrate, rigidly erect, subcylindrical to compressed, 

branched colonies probably attached to the substrate by encrusting bases. Outer skeletal walls probably thickened 

throughout life; this accretion allowed proximal trunks and 

branches to thicken greatly and suggests that the colonies 

grew up from the substrate to filter food from the water, 

much as do shelf species having similar colonies.

Seven new species, four autochthonous and three allochthonous, are described. Additional allochthonous material 

seems identifiable with five species known from deposits of 

middle Eocene to early Miocene age in Australia or India. 

The remaining material, apparently belonging to six genera, 

is inadequate for assignment to species.

INTRODUCTION

An assemblage of 18 species of cheilostomes from 

upper Eocene (Tertiary 6) beds on Eua, Tonga, includes the first known fossil deep-sea Bryozoa. The 

five species inferred to be part of this deep-water 

faunal element belong to four ascophoran genera, 

and four of the species are morphologically closely 

comparable to congeneric Holocene deep-sea species. 

A significant evolutionary history in the deep sea 

thus probably preceded the entombment of deepwater cheilostomes in sediments now cropping out

1 Department of Paleobiology, National Museum of Natural History, 

Smithsonian Institution, Washington, D.C. 20560

in Tonga. The species in this faunal element all had 

nonfenestrate, rigidly erect, subcylindrical to slightly flattened, branched colonies, in which calcareous 

accretion seemingly continued throughout life to 

thicken markedly the more proximal brancher If 

sirtli|ax heavily calcified zoaria characterize d^epwatel|||pecies generally, then other deep-water assemb^es may be preserved in Tertiary deposits

In addition to the deep-water element, 13 species 

occuring less commonly in the assemblage are irferred to have been transported to the site of burial from 

a shallow-bottom, tropical or subtropical habitat, 

probably not on a reef. These species belong to genera 

that are common in Tertiary deposits in the 

Australia-New Zealand region, and some of the. genera have virtually circumtropical distributions. Tongan specimens are identifiable with the follovring 

four Australian Tertiary species: Cellaria cucullata 

MacGillivray, from the upper Eocene Glenaulin Clay 

and Cape Otway beds of Brown (1958) ; and Canda 

fossilis Waters, Menipea innocua Waters, and Tubitrabecularia clypeata (Waters), from the lower Miocene Balcombian Stage. Tongan material also seems 

identifiable with Tetraplaria turgida Tewari and Srivastava, a species described from the middle Eo?ene 

Kirthar Stage of India.

Specimens of both shallow- and deep-water species 

are poorly preserved; a few inferred shallow-water 

specimens show abrasion. The material is from two 

samples collected from approximately the same outcrop about one-quarter mile north of Vaingana, Eua, 

Tonga (see "Foreword" and fig. 2), at 400 feet altitude. The samples are listed separately in tab1 ^ 1 

(sample 1, station 24686, collected by Y. Kendo, 

1967; sample 2, station 24745, collected by Wilfred 

Bryan, 1969) ; the differences between them appear 

to be within the expected sampling error. The material has been dated by Cole (1970) as late Eocene, 

and by Todd (1970) as from the Globigerina gor^anii 

planktonic foraminiferal zone.

El
E2 LATE EOCENE FOSSILS FROM EUA, TONGA

A less abundant assemblage of cyclostome Bryozoa 

in the same samples has not been studied.

I am indebted to Harry S. Ladd for the specimens 

on which this study is based and for comments on 

the manuscript; to Richard S. Boardman and Joseph 

E. Hazel for critical reviews of the manuscript; and 

to JoAnn Sanner and Lorenzo Ford for valuable technical assistance.

PALEOENVIRONMENTS

In the absence of living species in this assemblage, 

the conditions under which it lived and was buried 

can be inferred only from the geographic and bathymetric ranges of living congeneric species. All the 

Tongan Eocene species but one, Tubitrabecularia clypeata, have living congeners.

The geographic and bathymetric ranges of genera

can, of course, be equal to those of each included 

species, but in general they are appreciably greater. 

It is not surprising, therefore, that nine of the 15 

genera represented, or probably represented, in the 

Tongan Eocene assemblage include living species 

whose composite ranges extend more thar 45° latitudinally from the equator and from shallow depths 

to 200 meters or more, with shallow occurrences at 

both low and middle latitudes. These eur^thermal, 

eurybathic genera Beania, Cellaria, Chiastosella, 

Figularia, Menipea, Patsyella, Reteporellina, Schizoporella, and Spiroporina account for more than half 

the species and about 60 percent of the specimens in 

the assemblage (table 1). The Tongan species of two 

of these genera, however, are morphologically closely similar to living species having much more restricted ranges, as discussed below.

TABLE 1. Specimen abundance, other properties of cheilostome bryozoan species in two samples from upper Eocvne beds on

Eua, Tonga

[Estimated temperature tolerances are based on depth-latitude distribution of morphologically similar living species]

Species

Spiriporina kondoi, n. sp. _ .

Bifaxaria diaphyota, n. sp._~ ... ... ... _ _ 

Reteporellina ? sp. ._ _-_.. __-__ .__..._______ ___.

Bifaxaria bryani, n. sp. _____ . __.._ ... __ ______

Tubitrabecularia clypeata (Waters)-...... ___ .

Tetraplaria simata, n. sp. . . ... ... ... -

Tessaradoma bifax, n. sp. ... _.. . ...._

Canda fossilis Waters- ......................... _ ....

Tetraplaria cf . T. turgida Tewari and Srivastava... . __

Schizoporella aff. S. macgillivrayi Canu and Bassler__ 

Beania diademata, n. sp... ......_. ..........

Cellaria cucullata MacGillivray .... __. .. ......

Chiastosellat sp. __ .... __ ... _

Figularial sp. _ .___._ _. ___.____ 

Menipea innocua Waters ._. ___ ___ ._.._.___._

Patsy ellal sp. ____ _ ______ _ .... . .... . ____..

Triporula aff. T. biarmata (Waters) ...... ..... ..... ._ ...

Number of £

Sample 1

74

___ 31

______ 12

___ 2

__.._. 5

_.____-_ 3

.___ 5

..__ 3

_____ 0

_____ - 0

____. 2 

0

_____ 1

0

_____ 0

_____ 0

1

._ _ 0

samples

Sample 2

10

19

7

4

0

2

0

1

4

3

0 

1

0

1

1

1

0

1

tolerance

 _do 

Eurythermal

Eurythermal

__do___.

Thermophilic

___do.__._

Eurythermal 

Thermophilic

Eurythermal

do

 ..do .

do

___do__

Thermophilic

Inferred

form

Do.

Eschariform

Do.

Cellariiform

Do.

Reteporform

Cellariiform

Vincula.riiform 

Petraliiform

Cellariiform

Membraniporiform

Vincula.riiform

Eschar'form

Vinculsriiform

Membraniporiform

Five of the genera represented in the Tongan assemblage have Holocene depth-latitude distributions 

suggesting stenothermal tolerances. The known occurrences of Canda (see Harmer, 1926). Tetraplaria 

(see below), and Triporula (see Cook, 1967) are consistent with a thermophilic restriction to shoalwater, tropical or subtropical habitats. On the other 

hand, Bifaxaria seems to be cryophilic, occurring 

chiefly, perhaps exclusively as discussed below, at 

bathyal and abyssal depths. Tessaradoma appears to 

be unique among the genera in this assemblage in being cryophilic with extremely broad latitudinal and 

bathymetric ranges.

A paleoenvironmental interpretation of the Tongan assemblage thus depends upon the seemingly

anomalous association of the cryophilic genera Bifaxaria and Tessaradoma with thermophilic genera exemplified by Tetraplaria. The importance of the Holocene distributions of these genera and th^ expectation that their Eocene distributions conf orned to the 

same thermal control necessitate more detailed discussion than is available in previous literature.

DISTRIBUTION OF TETRAPLARIA

The living species of Tetraplaria are distributed 

nearly circumtropically (fig. 3). The onl^ tropical 

region in which the genus has not been found is the 

West African province, the cheilostome fauna of 

which has been extensively studied (see Ccok, 1968).
CHEILOSTOME BRYOZOA E3

 HOLOCENE

* MIOCENE 

A OLIGOCENE

# EOCENE

FIGURE 3. Geographic and stratigraphic distribution of Tetraplaria. Sources of data are Brown (1958), Canu and 

Bassler (1920, 1928b, 1929), Cheetham (1959; 1963), Ghiurca (1966),Harmer (1957), Haswell (1880), Kirchenpauer 

(1869), Kirkpatrick (1888), Labracherie (1968), MacGillivray (1895), Maplestone (1900, 1909), Mature (1968), 

Osburn (1914, 1940, 1952), Robertson (1921), TenisonWoods (1879), Tewari and Srivastava (1967), Thornely 

(1905, 1907), Waters (1881, 1883), and the following addiThe most widely distributed species is the IndoPacific T. ventricosa (Haswell), known under four 

names (Harmer, 1957), from the Amirante Islands 

and Seychelles (long 53°30' E.) eastward to the Fiji 

Islands (long 178°45' E.). All the known occurrences 

of T. ventricosa lie between latitudes 17° N. and 20° 

S. Three more names (Pollaploecium gilbertensis 

Maplestone; P. brevis Canu and Bassler; and Tetraplaria veleroae Osburn) probably refer to a second 

species distributed from the Gilbert Islands (long 

174° E.) eastward to the Galapagos (long 90°30' W.) 

and from just south of the equator to about latitude 

20° N. Two other species have constrastingly restricted distributions; the Atlantic T. dichotoma (Osburn) 

occurs only north of the equator (lat 17°55'-24°45' 

N.), whereas the Australian T. immersa (Haswell) 

is known only from the south (lat 9°55'-21°39' S.).

The thermal significance of the present latitudinal 

range of Tetraplaria is not known directly because 

bottom-temperature data are available for only one 

of the stations at which it occurs (26° C in April 

1902, at 36-38 m, Albatross sta. D. 4168, Hawaii). 

All the modern occurrences are in areas where the

tional specimens in the collections of the National Museum 

of Natural History, Smithsonian Institution: Tetraplaria 

sp. (Oligocene, Marianna Limestone, St. Stephens quarry, 

Ala.) ; T. tuberculata (upper Eocene, Crystal River lamestone of Cheetham (1963), Sepulga River bridge, BrooHyn, 

Ala.) ; T. australis (Oligocene, Janjukian Stage, Bird Rock, 

Torquay near Geelong, Victoria, Australia) ; T. australis 

(lower Miocene, Balcombian Stage, Altona Bay Coal Shaft, 

Port Phillips, Victoria, Australia).

surface waters average 20° C or more during the 

coolest month of the year. The Atlantic and Indian 

Ocean occurrences are all in shallow water, 11-18 m 

and 7-31 m, respectively. Bottom-water temperatures at these depths are no doubt only slightly cooler than surface water temperature. The Pacific occurrences, however, are less restricted in depth, five 

reported at more than 50 m and three of thes? at 

more than 100 m.

Two of the records at more than 100 m, one in the 

Philippines (104 m; Canu and Bassler, 1929) and 

one in the Galapagos (110 m; Osburn, 1952), appear 

not to be extreme if compared with the shallower occurrences, but the third, between 147 and 183 n in 

the Galapagos (Osburn, 1952), may be outside the 

living range of the genus. The jointed colonies of Tetraplaria readily disintegrate to form small, subcylindrical internodes that could be transported easily 

down submarine slopes. Encrusting attachment bases 

of colonies, which probably are more difficult to 

transport, have been described for only two oc?urrences, one at 110 m in the Galapagos (Osburn, 1952) 

and the other at 13 m in Indonesia (Harmer, 1957).

440-746 O - 71 - 3
E4 LATE EOCENE FOSSILS FROM EUA, TONGA

Because of the great morphological differences between zooecia making up the encrusting bases and 

zooecia in the erect parts of the colony, these bases 

may have been overlooked for some occurrences of 

the genus; it is unlikely, however, that this possibility would explain the depth difference in the two Galapagos occurrences, both reported by Osburn (1952). 

The 20° C or warmer survival range suggested by 

the depth-latitude distribution of the living species 

can be applied to fossil species of Tetraplaria only in 

the absence of morphological and distributional evidence indicating evolutionary changes in temperature 

tolerance. The nearest known counterpart in distribution and morphology to the widespread Holocene 

Indo-Pacific species T. ventricosa is T. turgida Tewari and Srivastava, from the middle Eocene of India, which may be represented in the Tongan material. Other fossil species, however, give the genus an 

appreciably broader Eocene latitudinal range (43° 

29' N.-380 S.) than it now has. Aside from T. simata, 

n. sp., in the Tongan Eocene, these species form two 

morphologically and distributionally distinct groups, 

one in the Eocene-Miocene of Australia (T. australis 

Tension-Woods, T. pedunculata, (MacGillivray)) and 

the other in the Eocene-Oligocene of the Atlantic and 

Gulf Coastal Plains (T. obesa Cheetham, T. petila 

Cheetham, T. tuberculata Canu and Bassler). The occurrence of a species apparently intermediate between the Australian and American groups in the 

Eocene of southwestern France (T. sp. Labracherie, 

1968) may record a Tethyan dispersal route between 

the two areas. The living American T. dichotoma, 

however, appears morphologically more closely related to T. turgida than to the American Eocene species. Thus it may represent a relict outlier of a oncecontinuous Indo-Pacific-western Atlantic relative of 

the two Indo-Pacific species. It seems unlikely, therefore, that the thermal significance of T. turgida was 

much different from that of living species of Tetraplaria, and the broader latitudinal distribution of the 

genus in the Eocene may be related to the generally 

broader tropical climatic belt of that time (see summary in Schwarzbach, 1963, p. 178-180).

DISTRIBUTION OF BIFAXARIA

The 14 nominal species of Bifaxaria as constituted 

here (see discussion p. Ell) are only slightly less 

limited latitudinally than Tetraplaria (fig. 4). In the 

Atlantic five species occur between 38° 25' N. and 9° 

05' S.; in the Pacific ten species are distributed from 

38°09' N. to 8° 18' S. Only one species, B. submucronata Busk, apparently is common to the two oceans 

(see Harmer, 1957; Hastings, 1966).

0.1

0.2

0.3

0.4

0.5

EXPLANATION

* T£S.?AftADOMA

* TETRAPLARIA

* BIFAXARIA

60° 50° 40° 3CT 20° 10° 

LATITUDE

10° 20° 30°

FIGURE 4. Depth-latitude distribution of living- species of 

three genera of cheilostome Bryozoa represented in upper 

Eocene beds on Eua, Tonga. Dots indicate single occurrences 

with specific depth-latitude data recorded; lines with median 

dots indicate single occurrences with only a rarge of depth 

or latitude recorded; lines alone indicate composite of occurrences with specific depth-latitude data recorded. The depth 

and latitude limits of each genus are shown b"T a polygon 

enclosing dots. Exclusion of the shallow-water occurrence of 

Bifaxaria is explained in the text. Sources of data for 

Tetraplaria and Tessaradoma are the same as in figures 3 

and 5; data for Bifaxaria are from Busk (1884), Canu and 

Bassler (1930), Harmer (1957), Hastings (1966), and 

Pourtales (1874).

Bifaxaria is distinctly a deep-water genus, having 

only four of 23 reported occurrences at depths less 

than 500 m. It occurs as deep as 3,477 m in the Atlantic and 5,719 m in the Pacific. Not all of the reported occurrences are at depths greater tl an 200 m,
CHEILOSTOME BRYOZOA E5

however, as suggested by Harmer (1957, p. 860; his 

Bifaxaria and Sclerodomus, see p. Ell). Diplonotus 

costulatum Canu and Bassler is, as recognized by 

Harmer (1957), a bifaxariid, indeed a member of 

Bifaxaria as here constituted; it was reported from 

two stations in the Galapagos at 72 and 1,252 m by 

Canu and Bassler (1930). The deeper occurrence 

(Albatross sta. D. 3408) is represented by five large 

and four small pieces of colonies (paratypes, USNM 

8503) retaining their covering membranes; these 

specimens were found with only two other cheilostome species, neither of which has been reported 

from other stations. Three small pieces, apparently 

broken from a single fragment (holotype, USNM 

8502), all devoid of covering membranes, record the 

shallower occurrence (Albatross sta. D. 2813); 30 additional species, either well-known shallow-water species or species each represented by several specimens, 

were reported from this station. Additional bulk material from the 72-m sample failed to yield specimens 

of B. costuktta. It is thus possible that the reported 

presence of this species at 72 m represents an accidental occurrence outside the living range of the genus, brought about, for example, by its transportation on or in a nektonic organism.

The only direct indication of the thermal tolerance 

of Bifaxaria is the 4° C bottom temperature reported for the 1,252-m occurrence in the Galapagos (Albatross sta. D. 3408) ; the presence of covering membranes may indicate that the specimens were alive 

when collected. Occurrences deeper than 2000 m in 

both the Atlantic and Pacific could correspond to bottom temperatures of about 2° C. By interpolation, the 

occurrences between 200 and 500 m, all in the 

Philippine-Indonesian region, could be as warrr as 

15° C and are probably no colder than 10° C. Thus, 

if the shallow-water Galapagos occurrence is ignored, the survival range for Bifaxaria appears to be 

between about 2° C and a few degrees less than 15° 

C.

If this temperature range is indeed the controlling 

factor for the depth of occurrence of Bifaxaria within its limited latitudinal distribution, it still does not 

explain the apparent absence of the genus from high 

latitudes, where it might be expected to occur in both 

shallow and deep water, or from the Indian Ocean. 

Other abiotic factors, geographic barriers, competition with other species, or a combination of factors,

FIGURE 5. Geographic and stratigraphic distribution of Tessaradoma. Sources of data are Burdon-Jones and TambsLyche (1960), Busk (1881, 1884), Calvet (1931), Canu and 

Bassler (1928a, 1930), LeDanois (1948), O'Donoghue 

(1924), Gautier (1962), Harmer (1957), Hincks (1880), 

Jullien and Calvet (1903), Kluge (1962), Lagaaij and Gautier (1965), Manzoni (1877), Nordgaard (1900, 1905, 1918, 

1927), Norman (1894, 1909), Osburn (1940), Ryland

(1963), Sars (1851, 1862), Silen (1935), Smitt (1868, 

1873), and the following additional specimens in the coUections of the National Museum of Natural History, Smithsoriian Institution: T. boreale (Holocene, Albatross sta. D.2062, 

42°17' N., 66°37' W., 275 m; Albatross sta. D.2573, 40°34' N., 

66°09' W., 3181 m; Albatross sta. D.2071, 41°56' N., 65°49' 

W., 207 m; Caroline sta. 102, 18°51' N., 64°33' W., 164-915 

m).
E6 LATE EOCENE FOSSILS FROM EUA, TONGA

might limit the geographic extent of Bifaxaria to 

only a part of the area within which it would encounter favorable temperatures.

DISTRIBUTION OF TESSARADOMA

The distribution of the three known living species 

of Tessaradoma (figs. 4, 5) is consistent with a similar temperature range to that inferred for Bifaxaria, 

from about 2° C to about 13° C. Tessaradoma, however, has a total depth range of 70 to 3,700 m and a 

latitudinal range of 77°05' N. to 33°32' S.

The greatest number of reports of this genus refer 

to the Arctic and Atlantic species T. boreale (Busk), 

whose latitudinal and depth ranges coincide with 

those of the genus. The two Pacific species, T. bipatens Harmer and T. striatum (Canu and Bassler), 

are known only from lat 30°45' N. to 0°12' N. and 

from depths of 469 to 1,252 m.

In the Arctic and Norwegian regions, Tessaradoma 

occurs virtually throughout the whole range of depth. 

Equatorward, the deepest records remain about the 

same, 3,500 m, but the shallowest occurrences show a 

gradual submergence from 70 m at lat 65°-75° N. to 

120 m at lat 45° N. to 150-160 m at lat 20°-25° N. to 

450-500 m at lat 0°-10° N. The relation of the southern hemisphere outlier to this trend is not apparent.

The equatorward submergence of Tessaradoma in 

the North Atlantic is consistent with a cryophilic 

stenothermy having an upper limit for survival of 

about 12° C. This limit must be slightly higher, however, for the genus occurs in the Mediterranean 

where bottom temperatures are never below about 

13° C, even at great depth (Furnestin, 1960).

Fossil occurrences of Tessaradoma have been reported from the Eocene of North Carolina and Alabama (Canu and Bassler, 1920), from the Miocene 

of Australia (MacGillivray, 1895), and from the Pliocene of Rhodes (Manzoni, 1877). The American 

species are not Tessaradoma but probably are referable to Semihaswellia ; the Australian species belongs 

to Tubiporella ; and the Rhodian species has not been 

found in subsequent study of the Pliocene fauna of 

that island (Pergens, 1887).

TONGAN CHEILOSTOME FAUNAL ELEMENTS

Association of Bifaxaria and Tessaradoma with 

Tetraplaria, Canda, and Triporula almost certainly 

indicates that the Tongan Eocene assemblage is a 

mixture of autochthonous and allochthonous elements. The habitats of these groups of species were 

tropical or subtropical but were separated bathymetrically by at least 85 m (fig. 4) arid very probably by more than 150 m, if the following assumptions 

are correct: (1) that the five apparently stenothermal genera had approximately the same thermal requirements and bathymetric distributions in Eocene 

time as at present; and (2) either that Tessaradoma 

had the same gradient of submergence approaching 

the equator from the south in the Eocene as it does 

approaching the equator from the north at present, 

or that its present minimum depth at tl^. equator 

characterized a broader latitudinal belt within a more 

widespread Eocene tropics. If, in addition, the extreme bathymetric occurrences of Holocene species 

of Tetraplaria and Bifaxaria are accidental and outside the living ranges of Holocene species of the two 

genera, this reinforces interpretation of bathymetric 

disjunction of the Tongan faunas.

The autochthonous element is assumed to include 

all of the species represented in the assemblage by 

significant numbers of specimens plus any others inferred to have the same thermal significance. Each 

of the first three species listed in table 1 is represented by at least three times as many specirrens as are 

any of the other species. The three abundant species 

plus two others having the same thermal significance 

make up almost 85 percent of the specirrens in the 

assemblage.

Of the well-represented species, one is a Bifaxaria, 

and the other two apparently belong to eurythermal 

genera, Spiroporina and Reteporellina. T"~is species 

of Spiroporina is morphologically comparable to an 

apparently cryophilic living species, S. brevitubulata 

Harmer, which occurs in the Philippine-Indonesian 

region at depths of 204 to 1,633 m (Harmer, 1957). 

Bifaxaria diaphyota and Spiroporina kondoi then indicate the cool- and deep-water character of the autochthonous element, and two other cryophilic species 

can be inferred to be part of this elenent, even 

though they are represented by far fewer specimens 

(table 1) ; these species belong to Bifaxaria and Tessaradoma. The autochthonous group of species, then, 

lived at a depth of probably more than 200 m and 

perhaps more than 1,000 m.

The allochthonous faunal element, as interpreted 

here, includes those species except Tessaradoma bifax 

which occur in minor frequencies (1-5; table 1) in 

the assemblage. These 13 species make up slightly 

more than 15 percent of the specimens.

Six species are inferred to have been th ermophilic 

and restricted to shallow water, probabl7 less than 

100 m deep. These include two species of Tetraplaria, 

a Canda, a Triporula, and apparently th ermophilic 

species of the eurythermal genera Spiroporina and 

Beania. The species of Spiroporina is comparable 

morphologically to S. longicollis (Canu and Bassler), 

which occurs in the Philippine-Indonesian region at
CHEILOSTOME BRYOZOA E7

depths no greater than 73 m (Harmer, 1957). The 

Tongan species of Beania has its nearest living counterpart in the Indonesian B. asymmetrica Harmer, 

known from depths no greater than 40 m (Harmer, 

1926). Six of the remaining species belong probably 

to eurythermal genera, and none of them is closely 

comparable with stenothermal living species. They 

are included tentatively in the allochthonous element 

because of their low frequencies of occurrence and 

the lack of evidence that they were restricted to cool 

water. The last species, Tubitrabecularia clypeata, is 

assigned to the allochthonous element even more tentatively, for the genus Tubitrabecularia is extinct. 

The probably closely related, living genus Siphonicytara is known from depths of 469 to 1,901 m in Indonesia (Harmer, 1957), but species of Tubitrabecularia occur in the Australian Tertiary with distinctly 

shallow-water genera.

The autochthonous element includes only typically 

benthic species, as indicated by growth forms that require attachment to a firm substrate. The allochthonous fauna, on the other hand, could have been benthic, and therefore transported laterally as well as 

vertically to a deeper burial site, or epiplanktonic, 

and therefore moved essentially only vertically to the 

sea floor. This faunal element includes a variety of 

growth forms, some of which, as in Beania diademata, both species of Tetraplaria, and Cellaria cucullata, are adapted to movable substrates including 

floating objects. If they consistently followed this 

mode of life, however, these species could have highly eurybathic distributions. Furthermore, Tongan 

specimens of Triporula and Chiastosella(l) are 

clearly adherent to nonbouyant substrates. Thus, part 

if not all of the allochthonous group of species was 

probably transported to the site of burial from a 

shallower bottom habitat.

Some, but by no means all, of the Holocene occurrences of Canda, Tetraplaria, and Triporula have 

been reported to be on coral, coral sand, or Lithothamnium associated with reefs. Other cheilostome 

genera commonly associated with Holocene reefs include Celleporaria, Nellia, Poricellaria, Steganoporella, and Thalamoporella, all known to occur in rocks 

of Eocene age in Europe and North America, as well 

as several genera not known from the Eocene. All of 

these genera have been reported from numerous 

Holocene localities in the Indo-Pacific. The likelihood 

of a reefal origin for the allochthonous Tongan element thus is not strong.

Four species considered to belong to the allochthonous, shallow-water Tongan faunal element Beania 

diademata, Canda fossilis, Menipea innocua, and Cellaria cucullata are members of families (Bicellariellidae, Scrupocellariidae, and Cellariidae) regarded as characteristic of the deep sea (Schopf, 

1969, p. 470). Each family, however, includes one 

genus or more that occurs eury- or stenobathically in 

shallow water.

MORPHOLOGY OF DEEP-WATER SPECIES

In contrast to the wide variety of colony forms 

displayed by the allochthonous component of the Tongan Eocene assemblage, the inferred deep-water species appear to have had more uniform colonies and 

therefore to represent more restricted adaptations 

(table 1). They belong to three ascophoran families, 

Bifaxariidae, Spiroporinidae, and Sertellidae. T'^re 

is no positive evidence that anascans were reprerented in the autochthonous faunal element, and the least 

calcified forms, Beania diademata and Canda fossilis, 

were apparently distinctly shallow-water allochthones in this assemblage. All the Tongan deep-water 

species have zooecial frontal shields susceptible of 

continued calcareous accretion throughout ontogeny. 

This property characterizes ascophorans having both 

known modes of frontal shield development (see 

Boardman and Cheetham, 1969, p. 222).

The growth forms of colonies of these deep-water 

species are not observable directly because all sx>ecimens are small zoarial fragments, the largest being 

less than a centimeter long. Some of these fragments 

preserve stubs of distalward branches, and from 

these and from changes in morphology associated 

with ontogenetic thickening of zooecial frontal 

shields, the form and size of colonies can be estimated. Within each zoarial fragment, frontal shields 

of proximal zooecia are slightly thicker than those 

of distal zooecia; other morphologic features, such 

as frontal pores, avicularia, and secondary orifices, 

may show correlated ontogenetic differences. In the 

three species having zooecia arranged biserially back 

to back (Bifaxaria bryani, B. diaphyota, and Tessaradoma bifax), the frontal shields of the two series 

of zooecia meet on the lateral surfaces of the t vanches, and zooecia placed more proximally on a fragment are slightly wider, viewed frontally, than those 

distal to them (see pi. 3, figs. 1, 2; pi. 4, figs. 4, 5; 

pi. 5, figs. 4, 5). B. diaphyota is sufficiently abundant 

that zoarial fragments having zooecia of differing 

widths form a series with overlapping ranges. Even 

though the differences within a fragment are b?.rely 

perceptible, the mean widths in all fragments having 

zooecia with thicker frontal shields are significantly 

greater than all those having thinner shields (see 

measurements, p. E13). A colony of B. diaphyota may
E8 LATE EOCENE FOSSILS FROM EUA, TONGA

have consisted of many such fragments arranged in 

a distalward branching form, with the base diameter 

of the stem almost twice as thick as the diameter of 

the branches near their growing tips. By analogy, 

it can be inferred that the two rarer biserial species 

had the same general growth form.

In Spiroporina kondoi, the zooecia are in four series opening radially around the branch. Distalward 

branching and ontogenetic zooecial changes suggest 

that otherwise the colonies were similar to the biserial ones. In Reteporellinaf sp., the two- to fourserially arranged zooecia all open on one zoarial 

surface. On the opposite sides of the fragments, 

extrazooecial calcareous material appears to follow 

the same ontogenetic gradient of thickening as do 

the zooecial frontal shields.

All these deep-water species appear to have had 

rigidly erect, nonfenestrate colonies with subcylindrical or slightly compressed branches (vinculariiform and eschariform; table 1) in which outer 

skeletal walls continuously thickened throughout life. 

The proximal ends of these colonies seem missing in 

the material at hand, but, in the absence of skeletal 

evidence of attachments for noncalcified rootlets or 

tendrils, it is assumed that colonies were attached 

directly to the substrate by small encrusting bases, 

as shown in the living deep-sea species Tessaradoma 

striatum by Canu and Bassler (1930, pi. 10, fig. 1). 

This morphology is similar to that of shelf cheilostomes having vinculariiform and eschariform colonies, and it appears to represent a similar adaptation 

for growth approximately perpendicular to the substrate, increasing exposure to the water column. This 

mode of growth seems advantageous in filter feeding.

A survey of living faunas has suggested that deepsea cheilostomes are generally characterized by 

bushlike commonly lightly calcified colonies attached 

to the substrate by noncalcified rootlets and tendrils 

which may hold them in a prostrate rather than an 

erect position (Schopf, 1968, p. 154; 1969, p. 470). 

This morphology was thought to be an adaptation 

for growth on the finely particulate substrates in 

the deep sea and possibly for detritus-feeding from 

the fine sediment (Schopf, 1969, p. 469-471). This 

characterization was based on genera in the anascan 

families Farciminariidae, Scrupocellariidae, Bicellariellidae, and Cellariidae (especially the genus 

Euginoma) and in one ascophoran family, the Bifaxariidae. The heavily calcified colonies of all the 

Tongan Eocene species inferred to live in deep water 

suggest that deep-sea cheilostomes may have adaptations comparable with those of shallow-water 

forms, and similar bifaxariids, spiroporinids, and

sertellids are, of course, known in the living faunas 

(see Harmer, 1957).

SYSTEMATIC PALEONTOLOGY

Suborder ANASCA Levinsen, 1909 

Family CHAPERIIDAE Jullien, 1888 

Genus PATS YELL A Brown, 1948 (?)

Patsyella? sp. 

Plate 1, figure 3

A single zoarial fragment from sample 1 may 

belong to Patsyella, a genus known from Oligocene 

to Holocene in New Zealand (Brown, 1952, p. 118, 

122).

The colony was apparently erect, the zooecia arranged in four alternating series, one on each face. 

There is no evidence of branching.

The zooecia are quadrate, their distel margins 

convexly rounded, their proximal margins concavely 

rounded. Deep grooves separate laterally adjacent 

zooecia. The narrow, smooth, rounded mural rim 

lies at the interzooecial boundaries, witliout intervening gymnocyst. The concave, imperforate, finely 

tuberculate cryptocyst slopes gently away from the 

proximal and lateral mural rim to the broadly ovate 

opesia which occupies the distal half of the frontal 

surface of the zooecium. On some zooecia, a pair of 

ill-defined ridges diverge proximally from the lateral 

mural rim and extend to the proximal end of the 

cryptocyst.

The opesia is bordered on its proximal and lateral 

margins by a narrow, smooth rim turned slightly 

under. Below the opesia, an occlusor-lamina runs 

from the distal wall to each lateral wall, forming 

small distolateral pouches opening frortally. The 

occlusor-laminae are more strongly developed in this 

specimen than is typical of Patsyella, though their 

development is considerably less than in Chaperia.

Entozooecial ovicells are present on several zooecia 

placed around the zoarial fragment without apparent 

pattern. The ovicell is immersed in the distal zooecium, just visible frontally as a small swelling on 

the cryptocyst. The opesiae of the ovicelled zooecia 

are slightly larger than those of nonovicelled zooecia.

Oral spines and avicularia are not present on the 

specimen.

Family CELLARIIDAE Hincks, 1880 

Genus CELLARIA Ellis and Solander, 1786

Cellaria cucullata MacGillivray 

Plate 1, figure 4

Cellaria cucullata MacGillivray, 1895, Royal Soc. Victoria

Trans., v. 4, p. 31, pi. 22, fig. 15.

Brown, 1958, Geol. Survey Victoria Mem., no. 20, p. 47, 

figs. 20, 21.
CHEILOSTOME BRYOZOA E9

A single internode fragment from sample 1 belongs to Cellaria cucullata. The preserved distal end 

of the internode shows three large, subcircular openings alternating with three small, triangular ones; 

the proximal end is broken. The uniformly hexagonal zooecia are arranged in six alternating series, 

in three of which, corresponding to the smaller distal 

openings, the zooecia terminate with the internode. 

The rounded-quadrate opesia lies at about zooecial 

midlength, lacks denticles, and is surrounded by a 

narrow, slightly raised rim from which the cryptocyst falls away more steeply distally to form, in some 

zooecia, the ovate hollow characteristic of the species 

(Brown, 1958, p. 47). Ovicells and avicularia were 

not found.

C. cucullata has been reported from beds of late 

Eocene age in Victoria, Australia.

Family BICELLARIELLIDAE Levinsen, 1909 

Genus BEANIA Johnston, 1840

Beania diademata, n. sp. 

Plate 2, figure 3

Zoarium unilaminate, apparently loosely encrusting, multiserial, with small, ovate fenestrae, visible 

only in basal view, between zooecia. Connecting tubes 

stout, joining each zooecium to six neighbors.

Zooecia very heavily calcified for genus, cucullate; 

proximal portion short, stout, forming part of proximal connecting tube; distal portion raised obliquely 

to overhang, but not rest upon, succeeding zooecium, 

hiding its proximal end from frontal view. Mural 

rim thick, rounded, finely tuberculate, slightly constricted in oral region, more constricted on one side 

which supports a large protuberant tubular collar 

probably marking attachment of avicularium. Spine 

bases distributed in four series: (1) bases of seven 

to nine small closely spaced spines placed along each 

lateral mural rim, proximal to oral constriction, 

paired bilaterally except for most distal spine base 

opposite apparent avicularium base, all projecting 

frontally; (2) bases of two small oral spines placed 

bilaterally on distolateral mural rim, projecting 

frontally; (3) bases of nine small spines placed in 

a symmetrical distolateral crown, one spine base 

occupying a medial position, around distal third of 

zooecium, just outside the spine bases on mural rim 

and more widely spaced, projecting distofrontally 

and frontolaterally; and (4) bases of five to eight 

larger spines irregularly distributed over basal surface. Opesia elongate, elliptical, occupying almost 

all of zooecial surface in frontal view.

Ovicells not observed.

Zooecial dimensions (in dk/x) measured in frontal

view on holotype are as follows (mean and standard 

deviation given to two decimal places for purposes of 

calculation only) :

Number 

Dimension measured

Length of zooecium.. _ .

Width of zooecium..-. 

Length of opesia ........... 

Width of opesia .. .. ...

7 

7 

7 

7

Mean

61.68 

40.68 

51.60 

29.28

Standard 

deviation

4.46 

1.73 

3.14 

1.14

Observed 

range

55-68 

38-43 

48-57 

27-30

Holotype, USNM 169234, sample 2. Upper Eocene, 

about one-quarter mile north of Vaingana, Eua, 

Tonga, at altitude 400 feet.

Beania diademata resembles the living species B. 

asymmetrica Harmer, 1957, in the placement of its 

(probable) avicularium and in the size of its zoarial 

fenestrae, the connection of its zooecia by six t ibes, 

and the distribution of its basal spines. B. asymmetrica has no spines on the mural rim or in a cMstolateral crown, however. The number of spines on the 

frontal side of the zooecium in B. diademata is similar to that in the living species B. hirtissima (Heller, 

1867), but the spines are distributed differently. Thus 

B. diademata, though represented by the single specimen, is highly distinctive.

Two fossil occurrences of Beania have been reported previously. MacGillivray (1895, p. 27) 

identified a poorly preserved early Miocene specimen 

from Australia, having only its basal surface observable, with B. spinigera (MacGillivray, 1880), 

a living Australian species, from which B. diademata 

differs in its smaller fenestrae and more numerous, 

differently distributed spines. The second fossil species, B. bermudezi Lagaaij (1968, p. 349, pi. 11, figs. 

11-14), described from middle and upper Eocene 

beds in Cuba, differs from B. diademata in hrving 

only four connecting tubes for each zooecium, differently arranged spines, and ovicells.

Family SCRUPOCELLARIIDAE Levinsen, 1909 

Genus CANDA Lamouroux, 1816

Canda fossilis Waters 

Plate 1, figures 1, 2

Canda fossilis Waters, 1881, Geol. Soc. London Quart. Jour.,

v. 37, p. 322, pi. 16, figs. 51, 52.

Waters, 1882, Geol. Soc. London Quart. Jour., v. 38, p. 261. 

Waters, 1883, Geol. Soc. London Quart. Jour., v. 39, p. 433. 

MacGillivray, 1895, Royal Soc. Victoria Trans., v. 4, p. 25,

pi. 3, figg. 12-14. 

Brown, 1958, Geol. Survey Victoria Mem., no. 20, p. 50.

Four zoarial fragments, all from sample 2, belong 

to Canda fossilis, described from lower Miocene beds 

(Balcombian Stage), in Victoria, Australia.

The growth form of these colonies apparently was 

unjointed, for one of them (pi. 1, fig. 2) exhibits a
E10 LATE EOCENE FOSSILS FROM EUA, TONGA

dichotomy with the zooecia continuously calcified 

from stem to both branches. The arrangement of 

zooecia in these biserial specimens is typical of Canda 

(see Harmer, 1926, p. 385) and conforms at the 

dichotomy to Harmer's (1923, p. 328) type 17 bifurcation. The inner zooecia at the proximal ends of 

the branches (denoted F and G by Harmer) meet in 

their proximal segments above the axillary zooecium 

(denoted E). Both zooecia F and G are provided with 

basal vibracula, as in living species of Canda.

The zooecia are slightly curved outward in frontal 

view; have a pair of symmetrically placed, small 

distal spine bases; and support a prominent scutum 

attachment just distal to the middle of their inner 

margin. The scutum attachment seems to correspond 

to the structure in the Australian specimens interpreted by Waters (1881, p. 322) as an avicularium 

or spine and by MacGillivray (1895, p. 26) as a 

sessile avicularium; it lies distinctly on the inner 

frontal surface of the zooecium, rather than on the 

lateral slope that forms the keel of the branch and 

on which avicularia commonly occur in living species 

of Canda (see Harmer, 1926, p. 384). The zooecial 

opesia is V-shaped as is characteristic of C. fossilis. 

In basal view, a markedly zigzag suture separates 

the zooecia.

Frontal avicularia occur only on the branched 

specimen on zooecia considerably proximal to the 

bifurcation, rather than at the bifurcation as is 

typical of some species of Canda (see Harmer, 1926, 

p. 384). The avicularia lie on the inner margins of 

the zooecia, just proximal to the scutum attachment. 

Their rostra, though broken, appear to be directed 

laterally toward the opesiae of adjacent zooecia.

The vibracula lie on the interzooecial sutures on 

the basal sides of the branches; their articular ends 

are just visible in frontal view. The rostral channels 

curve around prominent rootlet foramina.

Ovicells were not found in the Tongan material.

Genus MENIPEA Lamouroux, 1812

Menipea innocua Waters

Plate 2, figure 2

Menipea innocua Waters, 1882, Geol. Soc. London Quart. Jour, 

v. 38, p. 261, pi. 9, fig. 24.

A single zoarial fragment from sample 2 seems 

identifiable with Menipea innocua described from the 

lower Miocene (Balcombian Stage) of Victoria, Australia.

The colony apparently was not jointed, but dichotomously branched. The zooecia are in biserial, 

alternating rows. Their arrangement at the bifurcations appears to be consistent with Harmer's (1923, 

p. 328) type 17, with the inner zooecia of the branches meeting over the axillary zooecium. The outlines of zooecia of all rows are visibl0. on the 

otherwise smooth basal surface of the fragment. 

The arrangement of zooecia, especially as shown 

on the basal surface, differs markedly from that in 

the Australian Miocene species M. elongvta (Canu 

and Bassler, 1935, p. 14, pi. 3, figs. 6, 7) in which 

the morphology of the zooecia is similar, and similar 

to that in the living Philippines species M. crassa 

(Canu and Bassler, 1929, p. 221, pi. 10, figs. 10-13). 

The zooecia of the Tongan specimen differ from 

those of M. crassa in having more sharply raised 

mural rims enclosing more steeply plunging cryptocysts. The elongate gymnocysts of about half the 

zooecia support, just proximal to their mural rims, 

adventitious avicularia with pointed rostra directed 

laterally toward the outer margins of the zooecia. 

The avicularia are longer than those of M. crassa 

and, on the proximal sides of their chambers, are 

each provided with a foramen, possibly for attachment of a rootlet. The form and distribution of the 

adventitious avicularia differ from those in two 

Australian Eocene-Oligocene species, M. retrorsa 

and M. biaviculata, described by Maplestone (1900, 

p. 164, 165, pi. 17, figs. 8, 10).

Family CRIBRILINIDAE Hincks, 1880 

Genus FIGULARIA Jullien, 1886 (?)

Figularia? sp. 

Plate 2, figure 1

One zoarial fragment, from sample 2, may belong 

to Figularia. It is similar in its apparent growth 

form and zooecial morphology to F. kenleyi Brown 

(1958), p. 53, fig. 31), a species described from the 

upper Eocene of Victoria, Australia, tut differs 

from all known species of Figularia in its ovicells and 

avicularia.

The colony was apparently erect, with the zooecia 

arranged in four alternating series, one on each face. 

There is no evidence of branching.

The elongate-claviform zooecia have long, smooth 

proximal gymnocysts, extending as much as onethird the zooecial length and continuing as narrow 

strips along the lateral margins nearly to the distal 

end. Around the inner margins of the proximal and 

lateral gymnocyst are distributed 20 to 23 bases of 

costae or spines. On one zooecium at least the proximal two pairs of bases apparently wer?. parts of 

costae, for the most proximal pair reaches the midline where their inner ends are fused, and the next 

pair approaches the midline with their inner ends
CHEILOSTOME BRYOZOA Ell

fused to those of the proximal pair. A single slitlike 

lacuna is left between adjacent costae. The frontal 

surfaces of the costae are smooth and imperforate. 

The distal pair of bases on the nonovicelled zooecia 

are larger and have larger lumina than the more 

proximal bases and thus may be parts of oral spines 

rather than costae. F. kenleyi has similar frontal 

structure, but has fewer costae and no oral spines.

Just proximal to the remnants of its costal shield, 

each zooecium has an adventitious avicularium 

placed laterally on the proximal gymnocyst. The 

mandibular palate is elevated and inclined distolaterally, and the rostrum is directed medially, frontally, and slightly distally. Pivotal structures were 

not observed. Avicularia are lacking in F. kenleyi.

Broken ovicells are present on two zooecia. Unlike those of F. kenleyi, the ovicells are entozooecial, 

immersed in the distal zooecia, and visible frontally 

only as small swellings in their proximal gymnocysts. 

The larger pair of spine (?) bases is lacking on the 

ovicelled zooecia.

Suborder ASCOPHORA Levinsen, 1909 

Family EXECHONELLIDAE Harmer, 1957 

Genus TRIPORULA Canu and Bassler, 1927

Triporula aff. T. biarmata (Waters) 

Plate 2, figure 4

One poorly preserved zoarial fragment, encrusting 

a worn piece of decapod crustacean from sample 2, 

belongs to Triporula. Like T. biarmata (Waters, 

1882, p. 268, pi. 8, fig. 18), a species living in Australian waters and occurring as fossils in beds of 

early Miocene age in Australia and in beds of Oligocene-Pliocene age in New Zealand (Brown, 1952, 

p. 358), this specimen displays numerous small frontal pores and small, paired lateral-oral avicularia in 

addition to a median distal avicularium. The lateraloral avicularia, however, are directed medially, 

rather than distally as in T. biarmata and most other 

species of this genus, and their rostra commonly 

meet on the proximal lip of the orifice. Also, the 

zooecia of the Tongan specimen are less than half 

as large as those of T. biarmata (see Brown, 1952, 

p. 357; Cook, 1967, p. 341). T. verrucosa (Canu and 

Bassler, 1920), a Paleocene species from Georgia, 

has small zooecia, but its lateral-oral avicularia are 

placed more distally relative to the orifice than in the 

Tongan specimen and are directed distally.

The frontal pores of the Tongan specimen appear 

not to be stellate, but their original shape may not 

be preserved. Each pore, even in zooecia apparently 

near the growing margin of the colony, is surrounded 

by a distinct tubular collar. The three avicularia on

each zooecium are in series with the outer row of 

pores, and, on zooecia apparently at the growing 

margin, this row of pores lies frontally away from 

the dietellae from which they are separated by an 

interval of vertical wall, as noted by Cook (1967, 

p. 342) in living species of Triporula.

Family BIFAXARIIDAE Busk, 1884

Harmer (1957, p. 859) considered this family and 

and the family Sclerodomidae Levinsen, 1909, synonymous; so he combined them under the nam* Bifaxariidae. As discussed below, Harmer's (19?7, p. 

866) concept of Sclerodomus Levinsen, 1909, appears to be inconsistent with the characters of its 

type species, Bifaxaria denticulata Busk, 1884, 

which is morphologically unlike the other species included by Busk in Bifaxaria, and those included in 

Urceolipora MacGillivray, 1881. Also unlike tifaxariids, Sclerodomus sensu stricto and other genera, 

such as Cellarinella Waters, 1904, that have been 

assigned to the Sclerodomidae, have distributions 

including the Antarctic and subantarctic regions. 

Bifaxariids and sclerodomids should probably be 

maintained as separate families.

Genus BIFAXARIA Busk, 1884

The Tongan specimens described below as Bifaxaria bryani, n. sp., and B. diaphyota, n. sp., appear 

to be the first known fossil bifaxariids, and their 

affinities seem to be with the living species B. corrugata Busk, 1884, and B. papillata Busk, 1884. Both 

these living species were referred by Harmer (1957, 

p. 867-868) to Sclerodomus, but there are reasons, 

some of which were mentioned by Hastings (1966, 

p. 59), to question this assignment.

As constituted by Busk (1884, p. 79), Bifaxaria 

included a heterogeneous assemblage of eight species; the heterogeneity was recognized by Waters 

(1888, p. 15) and Levinsen (1909, p. 302-304), who 

established Sclerodomus for B. denticulata, the only 

species included in Bifaxaria having more than two 

series of zooids, sinuate secondary orifices, and median suboral avicularia equipped with complete crossbars. Harmer (1957, p. 861, 866) considered all the 

originally included species in which the colonie^ are 

not jointed, except B. abyssicola Busk, 1884, to belong in Sclerodomus. He implied that the development of secondary avicularia covering earlier frontal 

structures also distinguishes Sclerodomus fron Bifaxaria, but in B. corrugata secondary avicularia are 

lacking (Hastings, 1966, p. 60) ; the specimen on 

which Busk (1884, p. 80) noted their presence belongs to B. papillata (Hastings, 1966, p. 59). The

440-746 O - 71 - 4
E12 LATE EOCENE FOSSILS FROM EUA, TONGA

concept of Sclerodomus proposed by Harmer thus is 

too broad and probably should not include the biserial species. If the nonjointed species here considered to belong to Bifaxaria were separated generically from the jointed ones, a new genus would be 

required for them.

In both the Tongan species described below, the 

bases of the branches, where they join the colony 

stem, consist of two zooecia in opposition, back to 

back. This arrangement appears not to differ from 

that in the bipartite bases rami shown by jointed 

species of Bifaxaria (Harmer, 1957, p. 861) and 

suggests that there is little structural difference between the jointed and the unjointed biserial bifaxariids.

Bifaxaria bryani, n. sp. 

Plate 4, figures 4, 5

Zoarium rigidly erect, apparently not anastomosing, pinnately branched; branches given off singly, 

their distribution suggesting arrangement in alternating pairs from main stem. Stem and branches 

subcylindrical, consisting of two alternating series 

of zooids arranged back to back; at base of branch, 

first pair of zooecia oppose rather than alternate. 

Branches arise from frontal sides of stem zooecia, 

all zooecia thus open in plane of branching. Zoarial 

fragments apparently from proximal parts of colonies have diameters almost twice those apparently 

from distal parts. Basal attachments not found.

Zooecia with transversely hexagonal frontal surfaces, lateral portions of which wrap around lateral 

surfaces of branch so that in lateral view, adjacent 

zooecia are separated by narrow, slightly raised, 

markedly zigzag ridge. Viewed frontally, zooecia 

appear rounded rectangular, their width about fivesixths length in distal fragments and as much as IVa 

times length in proximal fragments. Frontal shield 

inflated, smooth except for narrow, discontinuous, 

irregularly sinuous, slightly raised submedian ridge, 

on each side of which are six to eight approximately 

alined longitudinal rows of oval to slitlike pores; on 

distal zooecia, frontal shields are thinner with submedian ridge more regularly positioned than on 

proximal zooecia. Secondary orifice terminal on 

frontal surface, slightly wider than long, rounded 

trapezoidal with the longest side distal; distal margin broadly arcuate; proximal margin almost 

straight-sided laterally, strongly indented medially 

by a prominent, pointed mucro which usually continues the frontal submedian ridge. Secondary orifices of presumed ovicelled zooecia not apparently 

different from those of nonovicelled zooecia.

Avicularia adventitious, of two positions: lateraloral and lateral. Lateral-oral avicularia small, 

paired, paralleling margins of secondary orifice, 

with rostra directed distolaterally. Lateral avicularia 

larger, single or paired, rarely occurring in greater 

numbers on zooecia at base of branch or distal to 

ovicell, lacking on distal zooecia except at points of 

branching; placed on lateral portions of zooecial 

frontal shield, near zigzag interzooecial boundary, 

commonly in an irregularly longitudinal line; rostra 

oriented distally, proximally, laterally, or medially, 

but rarely obliquely. Rostra of both laterpl and lateral-oral avicularia broadly spatulate; pivotal condyles are broad, rounded knobs at about midlength 

on palatal surface.

Ovicells, if present, completely immersed in distal 

zooecia, apparent externally only as swellings in 

their frontal shields.

Zooecial dimensions (in dk//,) measured in frontal 

view on six zoarial fragments (holotype and five 

paratypes) are summarized as follows (mean and 

standard deviation given to two decimal places for 

purposes of calculation only) :

Number 

Dimension measured

Length of zooecium : 

Distal zooecia __ .._._. .

Proximal zooecia _. _ _ Width of zooecium : 

Distal zooecia __..__ .. _

Length of orifice

Width of orifice

Length of avicularium :

Lateral __... ._.. _ ____ 

5 

13

5 

13

10 

10

18 

16

Mean

66.19 

71.27

56.78 

99.90

18.10 

20.10

10.41 

16.38

Standard 

deviation

3.50 

9.59

1.56 

14.71

1.81 

2.61

1.80 

4.04

Observed 

range

61-71 

57-91

55-59 

77-122

14-21 

17-25

7-15 8-22

Tested by Student's t, the difference in mean 

lengths of distal and proximal zooecia is not significant (0.05 level), and the difference in mean widths 

of distal and proximal zooecia is highly significant 

(0.01 level). The difference in mean lengths of lateral-oral and lateral avicularia is also Hghly significant.

Holotype, USNM 169241, paratype, USNM 169242, 

and 2 paratypes, USNM 169243, sample 2. Two paratypes, USNM 169244, sample 1. Upper Eocene, about 

one-quarter mile north of Vaingana, Eua, Tonga, at 

altitude 400 feet.

Bifaxaria bryani is most similar to the living 

species B. corrugata Busk, from which it differs in 

the frontal shield being smooth rather than longitudinally ridged between the rows of por^s, the secondary orifice having a prominent mucro, and the 

lateral portions of the frontal shield being equipped
CHEILOSTOME BRYOZOA E13

with avicularia in the more heavily calcified proximal zooecia. The presence of lateral avicularia in 

B. bryani links it with the living species B. papillata 

Busk, B. gigantea (Harmer), and B. rugata (Harmer) and with the Tongan Eocene B. diaphyota, n. 

sp., described below. Unlike the living species, the 

Tongan species appear to have the lateral avicularia 

no larger distal to ovicells and at the points of 

branching than at other locations.

As. in other species of Bifaxaria, the zooids in the 

proximal parts of colonies of B. bryani apparently 

differed markedly from those in the distal parts, 

chiefly as the result of ontogenetic changes in the 

frontal shield. The most conspicuous change (compare pi. 4, figs. 4 and 5) is the increase in shield 

thickness, resulting in doubling the diameter of the 

branch. As in B. corrugata (see Hastings, 1966, p. 

59-60), thickening took place without the development of frontal avicularia, except at the lateral 

extremities of the shield in B. bryani, so that the 

submedian ridge, the oral mucro, and the longitudinal rows of pores continue, for the most part, into 

the later ontogenetic stages with little change in 

form. Unlike B. corrugata, however, B. bryani shows 

no tendency to develop longitudinal ridges between 

pore rows and therefore lacks, at all stages, the 

corrugated appearance of the living species. The 

pattern of pore rows in B. bryani is interrupted 

around lateral avicularia on the more heavily calcified zooecia and on zooecia at the base of a branch; 

the pores around these avicularia appear to be radially arranged.

Bifaxaria diaphyota, n. sp. 

Plate 3, figures 1-7

Zoarium rigidly erect, apparently not anastomosing, pinnately branched; branches given off in 

opposing pairs. Stem and branches subcylindrical, 

consisting of two alternating series of zooecia arranged back to back; at base of branch, first pair of 

zooecia oppose rather than alternate. Branches arise 

from frontal sides of stem zooecia, all zooecia thus 

opening in plane of branching. Zoarial fragments 

apparently from proximal parts of colonies have 

diameters up to twice as large as those from distal 

parts. Basal attachments not found.

Zooecia with trapezoidal frontal surfaces, the 

widest margin at proximal end; lateral portions 

wrap around lateral surfaces of branch, so that, in 

lateral view, adjacent zooecia are separated by deep, 

moderately zigzag groove. Viewed frontally, zooecia 

appear almost triangular, with rounded apex at 

distal end; zooecial width varies from subequal in

length in distal fragments to nearly twice length 

in proximal fragments. Frontal shield inflated, incised medially with a deep longitudinal groove, on 

each side of which are few scattered large pores; 

frontal surface finely pitted, the pits in places alined 

in striate patterns; shields appear thick even on 

distal zooecia, thicker on proximal ones; on heavily 

calcified zooecia, buildup of avicularia imparts a 

papillose surface texture within which interzooecial 

boundaries become obscure. Secondary orifice terminal on frontal surface, strongly inclined distally, 

roughly semicircular with broadly rounded distal 

margin, nearly straight proximal lip slightly cleft 

by median frontal groove.

Avicularia adventitious, of two positions; lateraloral and frontal. Lateral-oral avicularia (not ol^ervable on most zooecia because of poor preservation) 

very small, paired, placed at distolateral corners of 

secondary orifice, facing slightly into peristome, 

directed distomedially. Frontal avicularia numerous, 

variable in position on surface of frontal shield, 

tending to bilaterally symmetrical placement; distal 

zooecia have two or three pairs of avicularia placed 

laterally, near zigzag interzooecial grooves; more 

proximal zooecia have three to five additional pairs 

placed more medially, usually including a pair placed 

on either side of median frontal groove in vicinity 

of secondary orifice; heavily calcified, most prcximal 

zooecia in material have many additional avicularia scattered over both median and lateral portions of frontal surface. Rostra narrowly to broadly 

spatulate, directed in apparently any direction. 

Pivotal condyles indistinct.

Ovicells not apparent in material studied.

Zooecial dimensions (in dk/u,) measured in frontal 

view on eight zoarial fragments (holotype and paratypes 169246-169252) are summarized as follows 

(mean and standard deviation given to two decimal 

places for purposes of calculation only) :

Number 

Dimension measured

Length of zooecium : 

Distal zooecia ..............

Intermediate zooeciaWidth of zooecium : 

Distal zooecia . ____________

Intermediate zooecia____ 

Proximal zooecia .______ 

Length of orifice 

(secondary) __________________ Width of orifice

Length of avicularium :

Frontal

1

3

25

2 

3 

25

31 

31

2 

94

Mean

(')

59.08 

65.35

63.84 

70.84 

89.82

19.46 

30.29

7.14 

10.13

Standard 

deviation

0) 

0)

10.70

(*) 

0)

8.84 

3.49 

5.22

0) 

1.99

Observed 

range

CO 

59-60 

51 07

60-67 

66-78 

76-113

10-25 

22-42

7-8 

7-16

1 Not calculated.

The difference in mean lengths of proximal zooecia
E14 LATE EOCENE FOSSILS FROM EUA, TONGA

and distal and intermediate zooecia is not significant (0.05 level, Student's t test) ; the mean width 

of proximal zooecia differs highly significantly from 

mean width of distal and intermediate zooecia (0.01 

level, Student's t test).

Holotype, USNM 169245; paratypes, USNM 

169246-169252; and 23 paratypes, USNM 169253; 

sample 1. Nineteen paratypes, NSNM 169254, sample 2. Upper Eocene, about one-quarter mile north 

of Vaingana, Eua, Tonga, at altitude 400 feet.

Bifaxaria diaphyota resembles one or the other 

of two living species, B. papillata Busk and B. rugata 

(Harmer), in the following characters: (1) its numerous frontal avicularia on the more proximal 

zooecia imparting a papillose surface texture to the 

colony; (2) its frontal pitting; and (3) its small 

lateral-oral avicularia partly hidden in the peristome. It differs from both of these species in lacking 

large avicularia at points of branching. The distinctive median frontal groove of B. diaphyota distinguishes it from all other known species of the 

genus.

The marked ontogenetic differences between proximal and distal zooids in B. diaphyota is apparently 

attributable to the development of frontal avicularia, 

unlike the ontogenetic changes noted in B. bryani 

above. This development also resulted in an approximate doubling of the diameter of branches. Frontal 

pores appear to have been lost in the process, but 

the median frontal groove and the surface pitting 

remained as the frontal avicularia multiplied.

Family SPIROPORINIDAE Harmer, 1957 

Genus SPIROPORINA Stoliczka, 1865

The suggestion (Brown, 1958, p. 55) that the 

type species of the genus Spiroporina, S. vertebralis 

Stoliczka, 1865, is a synonym of Eschara gracilis 

Lamarck, 1816, the type species of Porina d'Orbigny, 

1852, seems unlikely because the nature of their 

median frontal pores is different (see Harmer, 1957, 

p. 846-848, and Brown, 1952, p. 191-192). The relation between the ascus and the median frontal pore 

in the two species, and in the genera that they represent, appears to be distinctive, even though Harmer 

(1957, p. 844) expressed doubt about the significance of the difference between ascopores and spiramina. In S. vertebralis, the ascus opens through the 

sinus in the primary orifice (Harmer, 1957, pi. 56, 

fig. 2), although that opening is enclosed within the 

peristome, and the sinus is thus presumably the 

homologue of the ascopore in Porina gracilis.

Spiroporina kondoi, n. sp. 

Plate 4, figures 1, 2

Zoarium rigidly erect, delicate, dichctomously 

branched. Stems and branches slender, sub°.ylindrical, consisting of four to six alternating series of 

zooecia opening on all faces. Axes of stems and 

branches with longitudinal tubes.

Zooecia separated f rontally by shallow, inconspicuous grooves in apparently distal zoarial fragments, 

absent in apparently proximal ones; in frontal view, 

elongate-rhombic, convexly rounded distrlly, concavely rounded proximally. Zooecial length about 

three times width. Frontal shield slightly inflated; 

surface covered with short longitudinal grooves each 

containing a small pore; pores widely spaced, arranged in quincunx, those in marginal row ordinarily larger. Peristome completely hides primary 

orifice; moderately long, tubular, slightly inflated 

on ovicelled zooecia, free for as much as one-half 

the distance distal to spiramen, usually perforated 

proximolaterally by a pair of circular, slightly enlarged pores; free edge thin, cusped in distal zooecia, 

thick, rounded in proximal zooecia. Secondary orifice 

subcircular. Spiramen slightly larger than other 

medial frontal pores, surrounded by tubular, commonly protuberant collar.

Avicularia adventitious, represented by as many 

as five minute pits of irregular form distributed 

around free margins of apparently brohen peristomes. Pivotal structures not observed.

Ovicells completely immersed, apparent externally 

only as swellings in distal parts of peris tomes of 

ovicelled zooecia.

Zooecial dimensions (in dk/x) measured in frontal 

view on five zoarial fragments (holotyr° and 4 

paratypes USNM 169257, 169258) are summarized 

as follows (mean and standard deviation given to 

two decimal places for purposes of calculation only) :

Dimension

Number 

measured Mean

Standard Observed 

deviation range

Length of zooecium ... 

Width of zooecium _____

Length of orifice 

(secondary) _____________ Width of orifice 

(secondary) __ ______

_____ 34 

_____ 42

_____ 45

_-_ 45

103.89 

42.54

15.14

15.94

14.39 

3.93

5.73

5.55

82-132 

34-51

12-22

13-25

Holotype, USNM 169255, and 9 paratypes, USNM 

169256; sample 2. Paratype, USNM 169257, 3 paratypes, USNM 169258, and 70 paratypep, USNM 

169259, sample 1. Upper Eocene, about on°.-quarter 

mile north of Vaingana, Eua, Tonga, at altitude 400 

feet.
CHEILOSTOME BRYOZOA E15

Spiroporina kondoi resembles the living species 

S. brevitubulata Harmer, 1957, in its inconspicuous 

frontal pores placed in slitlike grooves; in S. brevitubulata, however, the colony is eight-serial, and 

the frontal wall supports numerous avicularia. The 

large lateral pores commonly present on the proximal 

part of the peristome distinguish S. kondoi from all 

previously known species of Spiroporina. Superficially, S. kondoi resembles Tessaradoma boreale 

(Busk, 1860), a widespread living cool-water species, 

which, however, lacks axial tubes in its branches 

and has only marginal pores on its frontal shields.

Spiroporina deliqua, n. sp. 

Plate 5, figures 1, 2

Zoarium rigidly erect, delicate, dichotomously 

branched. Stems and branches subcylindrical, consisting of transverse whorls composed of four 

zooecia each; zooecia opening on all four faces, those 

in adjacent whorls alternating in longitudinal position. Axes of stems and branches apparently without 

longitudinal tubes.

Zooecia without evident boundaries in frontal 

view, except for shallow depression separating 

zooecial whorls; interwhorl boundary forms V-shaped 

lobes directed proximally between laterally adjacent 

peristomes, thus marking lateral margins of zooecia. 

Zooecial length about three times width. Frontal 

shield inflated, closely and uniformly perforated with 

numerous small pores arranged in quincunx. Peristome completely hides primary orifice; moderately 

long, tubular, free more than half distance distal to 

spiramen on some zooecia, perforated with small 

pores similar to those on shield; free edge thin, 

slightly cusped. Secondary orifice subcircular. Spiramen much larger than other frontal pores, surrounded by prominent, tubular collar.

Avicularia adventitious, of two positions: peristomial and frontal. Peristomal avicularia represented by six or more minute pits of irregular form 

distributed around free margins of apparently 

broken peristomes. Frontal avicularia rarely present, placed just proximal to V's of interwhorl 

boundaries; oriented approximately longitudinally; 

rounded. Pivotal structures not observed.

Ovicells not found.

Zooecial dimensions (in dk//.) of five zoarial fragments (holotype and paratypes) are summarized as 

follows (mean and standard deviation given to two 

decimal places for purposes of calculation only) :

Dimension

Length of zooecium _.

Length of orifice 

( secondary ) ............

Width of orifice 

(secondary) ......_.....

Number 

measured

....... 42

....... 45

....... 48

....... 46

Mean

93.06

48.05

12.60

12.91

Standard 

deviation

13.09

4.37

1.81

1.59

Observed 

range

7C-124

37-54

10-18

10-18

Holotype, USNM 169260, paratype, USNM 16^261, 

and 3 paratypes, USNM 169262, sample 1. Upper 

Eocene, about one-quarter mile north of Vaingana, 

Eua, Tonga, at altitude 400 feet.

Spiroporina deliqua resembles the living species 

S. longicollis (Canu and Bassler, 1929) in its frontal 

perforations, long peristomes, and lack of axial 

tubes; it differs from that species in having fewer 

frontal avicularia and more slender branches with 

fewer zooecia per whorl. In both sets of characteristics, S. deliqua is similar to Porina tubulifera 

(MacGillivray, 1895), a species known from EoceneMiocene beds in Australia (Brown, 1958, p. 55) and 

from Oligocene beds in New Zealand (Brown, 1952, 

p. 193) ; the resemblance appears to be superficial, 

however, for in P. tubulifera the median frontal 

pore is an ascopore rather than a spiramen (Brown, 

1952, p. 192).

Genus TESSARADOMA Norman, 1869

Tessaradoma bifax, n. sp.

Plate 5, figures 4, 5

Zoarium apparently rigidly erect; branching not 

observed in fragments studied. Stems subcylincfrical, 

consisting of two alternating series of zooecia arranged back to back. Zoarial fragments apparently 

from proximal parts of colonies have diameters almost twice those apparently from distal parts. Basal 

attachments not found.

Zooecia lack distinct frontal boundaries, even in 

least heavily calcified specimens found; in lateral 

view, roughly zigzag double line of apparently marginal pores probably limits interzooecial boundary. 

In frontal view, zooecial width about five-sixths 

length in distal fragments, nearly li/2 times length 

in proximal fragments. Frontal shield inflated, thick 

in all fragments studied; surface covered with discontinuous, irregularly longitudinal ridges, fine on 

distal zooecia, coarse on proximal zooecia; lateral 

and proximal margins of shields on distal zooecia 

apparently marked by single row of pores, lacking 

on proximal zooecia; circumoral region slightly attenuated to form peristome. Secondary orifice subterminal on frontal shield at apex of peristome, 

subcircular; in distal zooecia, proximal part of
E16 LATE EOCENE FOSSILS FROM EUA, TONGA

secondary orifice sinuate, the sinus almost isolated 

from rest of opening by a pair of proximolateral 

denticles in peristome; in proximal zooecia, sinus 

lacking. Secondary orifices of ovicelled zooecia not 

apparently different from those of nonovicelled 

zooecia.

Avicularia adventitious, a pair placed on lateral 

extremities of frontal shield in series with apparently 

marginal pores, at about mid-zooecial length; lacking 

on proximal zooecia. Avicularian cavity rounded, 

without apparent pivotal structures.

Ovicells immersed in distal zooecia, apparent only 

from slight enlargement of peristomes of ovicelled 

zooecia and swellings in frontal shields of distal 

zooecia.

Zooecial dimensions (in dkjti) measured in frontal 

view on four zoarial fragments (holotype and paratypes) are summarized as follows (mean and standard deviation given to two decimal places for 

purposes of calculation only) :

Dimension

Number 

measured Mean

Standard Observed 

deviation range

Length of zooecium _ .___ Width of zooecium :

Intermediate zooeciaProximal zooecia ..

Length of orifice 

(secondary) _._____________ Width of orifice

Length of avicularium ____

15

8

4 

3

17

17

13

70.00 

60.08

66.57 

86.80

20.06

21.94

7.56

6.77 

2.01

4.17 

5.33

1.90

2.01

1.66

59-80 

59-65

62-72 

81-94

15-24

18-26

6-12

Tested by Student's t, the differences in mean 

widths of the distal, intermediate, and proximal 

zooecia are highly significant (0.01 level).

Holotype, USNM 169263, sample 2. Paratype, 

USNM 169264, and 2 paratypes, USNM 169265, sample 1. Upper Eocene, about one-quarter mile north 

of Vaingana, Eua, Tonga, at altitude 400 feet.

Tessaradoma bifax appears to be related to the 

living species T. striatum (Canu and Bassler, 1930), 

which differs from the Tongan species in having 

the frontal shields irregularly and coarsely grooved 

rather than ridged and the secondary oral sinus 

isolated as a spiramen in the distal zooecia and then 

persistent, though confluent with the orifice, in the 

proximal zooecia.

These two species and a third, T. bipatens Harmer, 

1957, differ from the type species of Tessaradoma, 

T. boreale (Busk, 1860) in their biserial colonies 

and the intimate association or complete confluence 

of their spiramina with the secondary orifices. T. 

striatum was originally assigned by Canu and Bassler (1930, p. 31) to their genus Diplonotos, the type 

species of which (D. costulatimi Canu and Bassler,

1930, by original designation) belongs to Bifaxaria 

as that genus is constituted above. Examination of 

the syntypes (USNM 8504) of Diplonotos striatum 

reveals that the primary orifice, contrar:T to the 

original description, lies at the base of a peristomial 

shaft that is very long in the heavily calcified parts 

of colonies, though the peristome is almost totally 

immersed in the thickened frontal shield. The sinuate 

opening described as a primary orifice thus is actually the secondary orifice, and, as mentioned above, 

this structure is isolated as a separate spiramen in 

distal zooecia (Canu and Bassler, 1930, pi. 10, fig. 3). 

With upgrowth of the peristome and surrounding 

frontal shield, the medial part of the bar separating 

the spiramen from the secondary orifice is discontinued so that the two openings are confluent in the 

more proximal zooecia. In T. bipatens, in vrhieh the 

peristome is less thoroughly immersed in the frontal 

shield, the spiramen is a tube extending up the 

proximal side of the peristomial collar in both distal 

and proximal zooecia (Harmer, 1957, p. 853), thus 

linking the biserial species with T. boreale, in which 

the spiramen is removed from the secondary orifice 

completely.

The ontogenetic changes in T. bifax, though not so 

clearly shown in this fossil material, thus appear to 

parallel those shown by T. striatum and to some extent, those shown by T. boreale. These changes are 

superficially similar to those noted above in species 

of Bifaxaria in that the diameters of stems approximately doubled by the thickening of the frontal 

shield. In the process, however, lateral rvieularia 

disappeared together with the apparently marginal 

pores, rather than multiplying as in the sx>eeies of 

Bifaxaria.

Family SIPHONICYTARIDAE Harmer, 1957 

Genus TUBITRABECULARIA Canu and BassHr, 1934

Tubitrabecularia is one of the four genera the assignment of which by Bassler (1935, p. 34; 1953, p. 

G211) to the family Tubucellariidae Busk, 1884, was 

questioned by Harmer (1957, p. 824). Tl^ family 

Siphonicytaridae was established by Harmer (1957, 

p. 892) for one of the four genera, Siphonicytara 

Busk, 1884, a living deep-water genus. A distinctive 

feature of Siphonicytara, the demarcation of the ascopore area by raised ridges, is also characteristic of 

Tubitrabecularia; however, additional ridge** are present in species of this genus, especially in the type 

species, T. elevata (Tenison-Woods, 1876) (see Waters, 1881, pi. 17, fig. 63). The frontal ridges of T. 

elevata greatly alter the frontal appearance of its 

highly calcified zooecia, making its morphologic interpretation difficult.
CHEILOSTOME BRYOZOA E17

Tubitrabecularia clypeata (Waters) 

Plate 6, figure 2

Porina clypeata Waters, 1881, Geol. Soc. London Quart. Jour.,

v. 37, p. 332, pi. 17, fig. 67. 

Tubitrabecularia proditor Canu and Bassler, 1935, Smithsonian Misc. Colln., v. 93, p. 18, pi. 4, fig. 10.

Five poorly preserved zoarial fragments, all from 

sample 1, belong to Tubitrabecularia clypeata, which 

was described from lower Miocene beds (Balcombian 

Stage) at Mount Gambler, South Australia, and Muddy Creek, Victoria. The specimens are four- to tenserial, those with fewer zooecial series being subcylindrical, and those with more being slightly compressed. Australian specimens, for example, USNM 

85887 from Muddy Creek, range from subcylindrical 

to highly compressed, and the holotype of T. proditor, 

USNM 85886, shows distalward flattening from a 

subcylindrical proximal end, perhaps the growth 

form of all fully developed colonies. There is no evidence in any of the material examined that the colonies were jointed (compare, Canu and Bassler, 1935, 

p. 18).

The zooecia in the Tongan specimens of T. clypeata are elongate and divided into two subequal 

frontal portions; a flat proximal area terminating 

distally in the tubular collar surrounding the ascopore, and an inflated distal peristome which is sessile 

for most of its length. The ridges demarcating these 

areas are less distinct in the Tongan specimens than 

in the Australian specimens, but this difference may 

be a result of preservation. The ascopore collar projects obliquely proximally, so that the ascopore faces 

proximally. A faint ridge runs distally from the ascopore up the midline of the peristome to the secondary 

orifice on some Tongan specimens (plate 6, fig. 2) ; 

this feature is not constant even in the better preserved Australian specimens.

The ascopore collar, in all material examined, rises 

from a slight depression and is bounded on either 

side by a small pore which seems to be in series with 

the larger pores that margin the peristome and the 

proximal frontal area. Lateral to each of the smaller 

pores is an adventitious avicularium of which the 

pointed rostrum extends slightly distally and up the 

side of the peristome of the laterally adjacent zooecium. Because of the lateral pore between it and the 

ascopore, the avicularium appears to be part of the 

zooecium whose orifice it flanks rather than of the 

zooecium whose ascopore it is near, as was assumed 

by Waters (1881, p. 332, pi. 17, fig. 67).

Ovicells were not found in the Tongan specimens. 

Frontally swollen areas on the holotype of T. proditor, interpreted as ovicells by Canu and Bassler

(1935, p. 18), appear to be solid masses of thick frontal shield.

Family SERTELLIDAE Jullien, 1903 

Genus RETEPORELLINA Harmer, 1933 (?)

Reteporellina? sp. 

Plate 6, figures 1, 3, 4

Twelve zoarial fragments from sample 1 and seven 

from sample 2, all poorly preserved, have zoarial and 

some zooecial features indicating that they may belong to Reteporellina.

The growth form of these specimens of Reteporellinat was apparently rigidly erect, unilaminate, dichotomously branched, and without anastomoses- The 

branches are two- or four-serial with indistinct zooecial boundaries rarely showing one or two proximolateral pores. The basal sides of the brancher are 

tuberculate and have a few irregularly transverse 

ridges.

Some of the badly worn peristomes have a labial 

pore and a rounded labial avicularium of about the 

same size as the pore, giving the secondary orifice a 

biperf orate-appearing proximal lip. Evidence of oral 

spines or denticles is lacking. The few ovicells present are all broken, so their frontal morphology is 

not observable.

Besides the labial avicularia, apparently present 

on all zooecia, some zooecia, especially in the vicinity 

of ovicells, have larger avicularia placed proximolaterally on their frontal shields. The spatulate rostra 

of the frontal avicularia are directed laterally. Large 

spatulate avicularia are also present on the basal 

sides of some branches, placed in the axils of bifurcations with their rostra directed obliquely distalvard.

In the absence of better preserved zooecial morphology, especially that of the ovicell, it is not possible 

to identify these specimens definitely with Reteporellina or to compare them with known species of that 

genus.

Family SCHIZOPORELLIDAE Jullien, 1883 

Genus SCHIZOPORELLA Hincks, 1877

Schizoporella aff. S. macgillivrayi Canu and Bassler 

Plate 5, figure 3

Two zoarial fragments, both from sample 1, appear related to Schizoporella macgillivrayi Canu and 

Bassler (1935, p. 29, pi. 9, fig. 5), which was described from the lower Miocene (Balcombian Stage) of 

Victoria, Australia. Like S. macgillivrayi, the Tongan specimens have transversely hexagonal zooecia 

separated frontally by salient ridges and have frontal shields closely perforated by small pores; these
E18 LATE EOCENE FOSSILS FROM EUA, TONGA

characters are better shown in the specimen illustrated by MacGillivray (1895, pi. 11, fig. 3), which 

Canu and Bassler (1935, p. 29) included in S. macgillivrayi, than they are in the holotype (USNM 

85859). The growth form of the Tongan specimens, 

however, is erect rather than encrusting, the orifice 

is more broadly sinuate, and there is little tendency 

for the zooecial axes to be disarranged as they are 

in the holotype of S. macgillivrayi. Avicularia are 

lacking on the Tongan specimens, but, contrary to 

the original description of S. macgillivrayi, they are 

present laterally on the frontal shields of some zooecia on the holotype; this observation accords with 

the suggestion of Brown (1958, p. 59) that avicularia 

might be present on some material from Victoria.

Genus CHIASTOSELLA Canu and Bassler, 1934 (?) 

Chiastosella? sp. 

Plate 4, figure 3

One zoarial fragment from sample 2, encrusting 

an unidentifiable piece of shell, may belong to Chiastosella.

One nearly complete zooecium and small parts of 

four others are preserved. The zooecium is rhombic 

and separated from the others by a distinct groove. 

Its frontal shield is inflated, perforated with large 

quincuncially arranged pores around all its margins 

and proximal to the orifice; the central imperforate 

portion is smooth. The interspaces between frontal 

pores tend to form radial ridges, as in C. porosa 

Canu and Bassler (1935, pi. 6, fig. 4). The orifice is 

semicircular distally, broadly sinuate proximally; its 

border is marked by a low peristome which supports 

four spine bases distally.

Lateral to this zooecium, the distal piece of the adjacent zooecium may have an ovicell. This structure 

is expressed frontally as a crescentic depression with 

a thick, perforate, raised ridge distal to the depression and suggests the immersed ovicells characteristic of the genus (see Brown, 1952, p. 219).

No avicularia were observed on this fragment.

In the absence of avicularia and of more definite 

ovicell structure, it is not possible to identify this 

fragment certainly as Chiastosella or to compare it 

with any known species of the genus. Species of this 

genus have been recorded from Australia and New 

Zealand, ranging from Eocene to Holocene (Brown, 

1958, p. 57).

Family TETRAPLARIIDAE Harmer, 1957 

Genus TETRAPLARIA Tenison-Woods, 1879

The fossil species referred to the genus Tetraplaria, including the type species, T. australis TenisonWoods, 1879, from beds of Eocene-Miocer^ age in. 

Australia, show more morphologic diversity than allowed in Harmer's (1957, p. 1053) diagnosis, which 

apparently was based only on studies of Holocene 

species. Some of this variation, especially in colony 

form, probably should not be included in th° concept 

of Tetraplaria.

Unlike T. australis and all the living species, some 

fossils have not yielded skeletal evidence of an erectjointed colony form, that is, internodes beginning 

with a bipartite connecting tube proximally and ending with a pair of bipartite bases rami distally. Cellaria schreibersi Reuss, 1848, from the uppev Eocene 

of Italy, placed in Tetraplaria by Canu and Bassler 

(1920, p. 367) and Braga (1963, p. 39; 1965, p. 231), 

not only lacks these structures but also exhibits dichotomous branching within single calcifsd fragments (Reuss, 1848, p. 63). Tetraplaria caudifera 

Canu and Bassler, 1920, from the upper Eocene of 

South Carolina, and Smittia centralis var. laevigata 

Waters, 1881 (presumably the taxon callec1 Smittea 

laevigata Waters in Canu and Bassler's 1923, p. 395, 

list of species of Tetraplaria), from the lower Miocene of Australia, also lack nodal structures and, 

additionally, have frontal pores limited to the margins of the shield, rather than dispersed uniformly 

over it as in all other fossil and all living species of 

Tetraplaria. These three species should probably be 

assigned to other genera. Examination of the syntypes of T. caudifera (USNM 64071) suggests that 

they may be conspecific with Hippopleurifera costulata (Canu and Bassler, 1920).

Brooding arrangements are variable in Tetraplaria. Hyperstomial ovicells are known in most species, 

including T. australis (see Brown, 1958, p. 58). Exceptions, in addition to the three nonjointed species 

mentioned above, are T. tuberculata Canu ?nd Bassler, 1920, from the upper Eocene of Florida, and T. 

iwimersa (Haswell, 1880), a living species from Australia, which has inflated brooding zooids (Harmer, 

1957, p. 1055). In T. australis the ovicell is deeply 

immersed in the distal zooecium (Brown, 1958, p. 58J, 

whereas in all other ovicelled species it is prominent, 

especially so in the Florida late Eocene species T. 

petila Cheetham, 1963, and T. obesa Cheetham, 1963.

In three living species, T. ventricosa (Haswell, 

1880), from the Indo-Padfic, T. dichotoma (Osburn, 

1914) from the Gulf of Mexico and Caribbean, and 

T. gilbertensis (Maplestone, 1909), from the Gilbert 

Islands, Hawaii, and the Galapagos, the orifices of 

ovicelled zooecia are larger than those of nor ovicelled 

zooecia. This dimorphism has not been noted pre-
CHEILOSTOME BRYOZOA E19

viously in fossils referred to Tetraplaria, but it is 

prominent in one of the two Tongan species, T. simata, n. sp.

Apart from the three apparently nonjointed species, which seem not to belong in Tetraplaria, avicularia are known in T. australis. According to Brown 

(1958, p. 58), specimens having avicularia are limited to the earlier populations of this species. The Tongan specimens, which are approximately coeval with 

the earliest populations of T. australis, do not have 

avicularia.

Tetraplaria simata, n. sp. 

Plate 7, figures 1, 4, 5

Zoarium erect-jointed, consisting of quadriserial 

internodes of four or five alternating pairs of auto70

60-

50-

40-

30-

20-

10-

o

O CD

o

i o

T

1

* 

§

2 ' 3 ' 4 ' 5 

AUTOZOOECIA KENOZOOECIA

FIGURE 6. Variations in width of successive pairs of autozooecia (1-5) and distal kenozooecia in five internodes of 

Tetraplaria simata, n. sp. Open circles, holotype (third pair 

of autozooecia ovicelled); closed circles, paratypes. One 

paratype has only four pairs of autozooecia preceding kenozooecia. A few zooecia in paratypes were not measured because of poor preservation.

zooecia and one pair of distal kenozooecia bearing 

bases rami; one pair of autozooecia can bear ovicells. 

Internodes stubby, tapered proximally, blunt distally, the proximal two-thirds to three-fourths slightly 

flattened in plane parallel to frontal surfaces of ovennumbered pairs of zooecia; these zooecia thus1 are 

wider than the first two odd-numbered pairs (fi£T. 6). 

Proximal end of internode is an imperforate, bipartite tube, slightly flattened in same plane as internode, formed from attenuated caudal portions of first 

pair of zooecia. Distal end of internode is a pair of 

elliptical bases rami with long axes oblique to axis 

of internode, on small kenozooecia slightly below distal margins of last pair of autozooecia, and, in some 

specimens, recessed below frontal surfaces of autozooecia proximal to them. Opening of basis rami bipartite.

Autozooecia separated frontally by narrow ridges. 

Zooecial length decreases distally within each internode (fig. 7) ; first through third pairs of zooecia 

show marked decrease in length, fourth pair no significant change, and fifth pair, where present, slight 

decrease. Widths of first and third pairs of zooecia 

about five-sixths those of second, fourth, and (where 

present) fifth pairs; widths of ovicelled zooecis and 

of all succeeding zooecia greater than those of corresponding pairs in nonovicelled internodes (fig. 6). 

First pair of zooecia elongate-claviform; second pair 

rhombic with distal corner convexly rounded; all following pairs transversely hexagonal, rounded concavely on proximal side and convexly on distal side. 

Frontal shield inflated, uniformly perforate ercept 

on caudal portion of first pair; pores small, numerous, 

quincuncially arranged. Orifice terminal on frontal 

shield, very slightly inclined distally; distal portion 

semicircular; proximal sinus broadly rounded, apparently lacking condyles; orifices of nonovicelled 

zooecia about four-fifths as large as those of ovicelled zooecia. Oral spines lacking.

Kenozooecia rounded-rectangular; about one-third 

as large as autozooecia; distal half occupied by oblique basis rami; proximal half covered with inflated, 

finely perforate frontal shield.

Ovicells present on both zooecia of third pair in 

some internodes (seen in one internode) ; hyperrtomial, prominent, covering proximal five-sixths of distal zooecium. Frontal cover uniformly and finely perforate, except for semicircular strip around orifice; 

set off from frontal shields of distal and prorimal 

zooecia by narrow ridges.

Avicularia lacking.

Zooecial dimensions (in dkjn) measured in frontal 

view on five internodes (holotype and paratypes) are
E20 LATE EOCENE FOSSILS FROM EUA, TONGA

110-

100-

90-

70-

50-

40-

30-

20-

10-

t r

2 ' 3 ' 4 ' 5 

AUTOZOOECIA KENOZOOECIA

FIGURE 7. Variations in length of successive pairs of autozooecia (1-5) and distal kenozooecia in five internodes of 

Tetraplaria simata, n. sp. Specimens and symbols as in 

figure 6.

summarized as follows (mean and standard deviation given to two decimal places for purposes of calculation only) :

Number 

Dimension measured

Length of autozooecium :

Width of autozooecium :

Length of zooecial orifice:

Width of zooecial orifice :

Length of kenozooecium _..... 

Width of kenozooecium ... _ .

9 

8 

9 

8 

6

9 

8 

9 

8 

6

36 

2

36 

2 

2 

2 

6 

6

Mean

105.93 

80.85 

59.17 

62.48 

54.74

46.67 

59.54 

53.85 

64.16 

62.58

15.89 

18.90

16.50 

19.74 

50.40 

54.60 

30.94 

21.14

Standard1 

 deviatior

7.35 

7.04 

4.19 

5.02 

2.89

3.57 

.98 

3.87 

4.48 

6.01

.70 

.42

.82, 

.42 

.00 

4.20 

3.83 

1.49

Observed 

range

100-124 

69 94

55-67 

56-71 

50-57

41-55 

58-62 

46-60 

56-71 

57-71

14-17 

18-19

14-18 

19 20

50 

50-59 

25-38 

19-24

The differences between means were tested by Student's t with the following results (significant 

= 0.05 level; highly significant =0.01 level) :

Dimension Means tested Difference

Width of zooecium ....._.....

Length of zooecium......_.._.____...First versus second pairs.

Second versus third pairs. 

Third versus fourth pairs. 

Fourth versus fifth pairs. 

..First versus second vs.

third pairs. 

First versus third vs.

fourth pairs.

Second versus fourth pairs. 

Fourth versus fifth pairs. 

Length of zooecial orifice....... Nonovicelled versus

ovicelled zooecia. 

Width of zooecial orifice.__ ._.._ .. do_._-__.

Highly significant.

Do.

Not significant. 

Highly significant.

Do.

Do.

Sigrifiicant. 

Not significant. 

Highly significant.

Do.

Holotype, USNM 169276; paratype, USNM 

169277; sample 2. Paratype, USNM 169278, and 2 

paratypes, USNM 169279, sample 1. Upper Eocene, 

about one-quarter mile north of Vaingana, Eua, Tonga, at altitude 400 feet.

Tetraplaria simata is distinguished by its slightly 

flattened internodes having the even-numbered pairs 

of autozooecia distinctly wider than the first two oddnumbered pairs; by the regular distalward decrease 

in lengths of the first three pairs of autozocecia in an 

internode; and by the combination of pronrinent ovicells, broadly sinuate orifices which are dimorphic in 

association with brooding, and ridges separating zooecia. If the limited variation in number of autozooecial pairs per internode, four or five, is significant 

in this small sample, this character would also differentiate T. simata from all other known species of 

the genus.

Although the widths of the first four pairs of autozooecia of T. simata (fig. 6) differ significantly statistically, those of the first and third pairs overlap 

broadly, as do those of the second, fourth, and fifth 

pairs. Except for the two ovicelled zooecia forming 

the third pair in one internode, there is almost no 

overlap between the two groups of autozooecial pairs.
CHEILOSTOME BRYOZOA E21

This difference in width is correlated with the flattening of the proximal part of the internode.

The third to fifth pairs of autozooecia in the ovicelled internode are wider than their counterparts in 

the nonovicelled internodes (fig. 6). The greater 

width is apparently a direct accommodation to the 

size of the ovicell, as it is restricted to the ovicelled 

and more distal zooecia. Thus, the ovicelled internode 

began growth with zooids like the first pair of zooids 

in the nonovicelled internodes and then, beginning 

with the ovicelled zooids, developed a different morphology.

The successive, pronounced distalward decreases 

in the lengths of the first three pairs of autozooecia 

within each internode (fig. 7) appear to follow an 

astogenetic gradient. If one can assume that all of 

the internodes beyond the unknown encrusting base 

of the colony had the form of the specimens described 

here, the astogenetic zonation in T. simata is of the 

cyclic type described by Boardman, Cheetham, and 

Cook (1970, p. 300, fig. 4), with each internode comprising subsequent zones of both astogenetic change 

and astogenetic repetition. The number of generations of zooids within a zone of repetition in T. simata, however, appears drastically limited compared to other cheilostomes in which cyclic zonation has 

been described.

In an internode having just four pairs of autozooecia preceding the distal kenozooecia, the zone of 

astogenetic repetition appears to consist of the fourth 

pair of autozooecia, which do not differ significantly 

in length from the third pair, and the pair of kenozooecia, which can be considered positional polymorphs similar to zooecia making up monticules in 

trepostomes (Boardman and others, 1970, p. 303). 

Where present, a fifth pair of autozooecia would thus 

also be included in the zone of repetition, and their 

slight, but statistically significant, decrease in length 

from the fourth pair could be regarded either as a 

chance variation because of the small sample or as a 

further expression of positional polymorphism. That 

this difference may be a chance variation is suggested by the broad overlap between the fourth and fifth 

pairs, as compared to no overlap of the first three 

pairs (fig. 7).

Alternatively, the slight decrease in length of the 

fifth pair of autozooecia could be considered the start 

of a series of astogenetic changes continuing into the 

next internode. This interpretation seems unlikely 

because it would restrict the kenozooecia to zones of 

change and because the zone of change would include 

zooecia showing first a decrease in length (fifth pair 

of autozooecia to kenozooecia), then an increase

(kenozooecia to first pair of autozooecia in nex* internode) , and again a decrease (first to third pairs 

of autozooecia).

The decreasing lengths of autozooecia in each internode reduce the distances between the distal margins of alternating pairs toward the distal end of the 

internode. If all pairs of zooids were the same length, 

the last two pairs would be half a zooecial length out 

of phase, and the kenozooids would have to be more 

than half as long as the autozooids in order to hold 

the bases rami beyond the ends of the last pair of 

autozooids. In T. simata the kenozooecia are less than 

a third as long as the longest autozooecia (fig. 7). 

In other species of Tetraplaria (see T. cf. T. turgida 

below), the autozooecia remain half a length out of 

phase and are followed by a relatively longer pair of 

kenozooecia.

Tetraplaria cf. T. turgida Tewari and Srivastava

Plate 7, figures 2, 3

1 Tetraplaria turgida Tewari and Srivastava, 1967, Jour. Geol. 

Soc. India, v. 8, p. 26, text-fig. 2 (4, 4a).

Three specimens, all from sample 2, may belorg to 

Tetraplaria turgida which was described from the 

middle Eocene (Kirthar Stage) of Kutch, India.

Although not shown in Tewari and Srivastava's 

(1967) drawings, frontal perforations seem to be 

implied in their description (frontals "covered by 

tremocysts," p. 27). All the Tongan specimens have 

large, prominent, evenly distributed frontal pores.

One complete internode, consisting of five pair? of 

autozooecia plus a distal pair of kenozooecia each 

bearing a bipartite basis rami, has ovicells. T'^se 

are borne on both zooecia of the third pair, as are 

those on the specimen illustrated by Tewari and Srivastava, and as in the latter, the ovicells are prominent, rather than immersed in the distal zooecium.

Tewari and Srivastava compared this species with 

T. australis in which the ovicells are deeply immersed 

in the distal zooecium (Brown, 1958, p. 58). T. australis also has the frontal shield covered with fine 

tubercles between which are exceedingly small pores, 

which were overlooked in Tenison-Woods' (1879, p. 

61) original description, and has the orifice interrupted proximally by a narrow, cleftlike sinus.

The Tongan specimens, and presumably the Indian 

specimens, more closely resemble another Australian 

species, T. pedunculata (MacGillivray, 1895), than 

they do T. australis. In T. pedunculata, the frontal 

shield is coarsely perforate and the ovicell (present 

in USNM 169283, Balcombian, Mitchell River, Biirnesdale, Victoria; not previously noted) is prominent ; the oral sinus, however, is narrow, and the zooecia are separated by prominent ridges.
E22 LATE EOCENE FOSSILS FROM EUA, TONGA

The internodes of the Tongan material appear to 

consist of variable numbers of autozooecial pairs. In 

addition to the five-paired complete internode, one 

specimen broken at both ends has six pairs, and the 

third, seemingly missing only a small part of the 

proximal zooecia and preserving the bases rami distally, shows only three pairs. In this respect, the Tongan specimens resemble living species of Tetraplaria, 

such as T. ventricosa (Haswell, 1880), in which 

Harmer (1957, p. 1054) described single colonies 

having the number of pairs of zooecia per internode 

ranging from one to ten or more.

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 1928a, Fossil and recent Bryozoa of the Gulf of Mexico 

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 1928b, Bryozoaires des lies Hawaii: Soc. Sni. Seine et 

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CHEILOSTOME BRYOZOA E23

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 1909, The Polyzoa of Madeira and neighbouring islands:

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 1940, Bryozoa of Puerto Rico with a resume of the West

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E24 LATE EOCENE FOSSILS FKOM EUA, TONGA

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 1882, On fossil cheilostomatous Bryozoa from Mount 

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INDEX

[Italic page numbers indicate major references and descriptions]

Page 

A

abyssicola, Bifaxaria ........... . ...... .. ... ...Ell

Acknowledgments ... ..........._ ..._..._..._. 2

Anasca ........._.... ........._.__.._._.. ._...._..__ 8

Ascophora ...... . ._ ......_......... .. __. 11

asymmetrica, Beania ...................... ....7, 9; pi. 2

Australian Tertiary species . ... _ ___.. 1

australis, Tetraplaria ....................... ......4, 19, 21

B 

Beania ....... ................ .... ....2, 6, 7, 8

asymmetrica ____.__..___...._...__.. ...7, 9; pi. 2

bermudezi ..............................._ .............. 9

diademata .............................._.-2, 7, 9; pi. 2

hirtissima ... ....___....._....__.. _.._._..._.. 9

spin igera __...............__..............-....-................... 9

bermudezi, Beania ........................ ..___ __...__......_ 9

biarmata, Triporula ___..._._...__._.._....___._.2, 11; pi. 2

biaviculata, Menipea ........... ..._.. ._...__._.__. -10

Bicellariellidae _.......... .... ...........................8, 9

bifax, Tessaradoma .......................2, 6, 7, 15; pi. 5

Bifaxaria ...................................2, 4, 5, 6, 11, 13,16

distribution ... ._..._._._.___.. ................. 2

ontogenetic differences __...._...._ _.__. _ .. 14

abyssicola _..._... _..._.......__-.__._._.____ 11

bryani ....................._.___......2, 7, 11, 12, 14; pi. 4

corrugata, .......................... ._...... 11, 12, 13

costulata .........................____...__...._ ............ 6

denticulata ......_ ....-.-... .-.-... .._ .. -11

diaphyota ... ... ......2, 6, 7, 11, iS; pi. 3

gigantea . .._.-.-. ....._____.._..._ 13

papillata ........... ..._... . ......11, 13, 14

rugata ........ .. .....................................13, 14

sitbmucronata ...._._.................._____________.__ 4

Bifaxariidae .................__......._ ............__ .7, 8, 11

bipatens, Tessaradoma .... ._......_ _._6, 16

boreale, Tessaradoma ._. _....... ._ 6, 15, 16

brevis, Pollaploecium ..__..._..__.. . ..... . 3

brevitubulata, Spiroporina ...._._ ... 6, IB

bryani, Bifaxaria . ............2, 7, 11, 1%, 14; pi. 4

Canda ......... .._ _._.............__..2, 6, 7, 9, 10

fossilis . ...-... . I, 2, 7, 9; pi. 1 

caudifera, Tetraplaria .....___..._......._...._.._....18

Cellaria .........._ ..... ............... .. ..........2, 8

cucullata - . ... . .1, 2, 7, 8; pi. 1

schreibersi ................... _. .18

Cellariidae .... ...... .. 8

Cellarinella . .-..... _ . ........ . ...11

Celleporaria ......._.._.____..._..__._........_......... 7

centralis laevigata, Smittia .....__ __....._.......18

Chaperiidae ....... ..-..... ......... -. 8

Chiastosella ._..._ .........._..___.__..._.__2, 18

porosa .........._.____.......__. ...... . .18

sp .__..... ___..___. .......... . 18; pi. 4

clypeata, Tubitrabecularia _.._. 1, 2, 7, i7; pi. 6 

Cole, W.S., age determinations .... ........... 1

Colony forms, deep-water species . ... 7 

corrugata, Bifaxaria ................. ..........11, 12, 13

costulata, Bifaxaria ....______________._ 5

Hippopleurifera ..._._....._._..._......_....._.18

costulatum, Diplonotus . ............. . 5, 16

craasa, Menipea ...... .... ___.__........ ... 10

Cribrilinidae ............._..._.._... ....... .......10

Page 

Cryophilic genera ..... ............... ... . . E2

Cyclostome Bryozoa _______......_._.. . ............. 2

cumllata, Cellaria . 1, 2, 7, 8; pi. 1

D

Deep-water species, characteristics ...... ... - 7

deliqua, Spiroporina _ . 2, IS; pi. 5 

denticulata, Bifaxaria ........_....__.._ 11

diademata, Beania _.._ . 2, 7, 9; pi. 2 

diaphyota, Bifaxaria ...... 2, 6, 7, 11, IS; pi. 3

dichotoma, Tetraplaria ................ .. 3, 4, 18

Diplonotos ..... __ . 16

costulatum ... ........ ....-.. ...5, 16

striatum ......_....._.._....._......._..._.__....16

E 

elevata, Tubitrabecularia .............. _ 16

elongata, Menipea ........_........._. ............ __. .10

Eschara gracilis ._._............_...._ -14

Eua, geology . _ _._ . Ill 

relation to Tonga Trench ....... ........... -Ill

Euginoma ........ ...................................................... 8

Eurybathic genera ......._.._____..... 2

Eurythermal genera .._................................. _ 2, 7

Exechonellidae _........._......_.._ _ 11

Farciminariidae . __ .. . 8

Faunal element, allochthonous ............_.... ...6, 7

autochthonous ..______.____ ..._..6, 7 

Tongan cheilostome ... ___ 6

Figularia ....... ........................................_......... ..2, 10

kenleyi ............................................... ... 10, 11

sp ........ ._ . ........................10; pi. 2

Foreword, by H. S. Ladd .. ///

Fossil collection, Eua, Tonga ____ _..V

fossilis, Canda _..... _...._..._...... I, 2, 7, 9, pi. 1

G

Geographic ranges, Tongan Bryozoa _ ... 2 

gigantea, Bifaxaria ......... ...____._____...____ ........13

gilbertensis, Pollaploecium ............._. ....._..._ 3

Tetraplaria ................................................... 18

Globigerina gortanii ...................................... .... 1

gortanii, Globigerina ..........................._.......... _____ 1

gracilis, Eschara .................................... .......... _ 14

Porina ......................................................... ..14

H, I 

Hippopleurifera costulata ...................._..__.. -18

hirtissima, Beania .................................................. 9

Hoffmeister, J.E., cited ... _ -IV

immersa, Tetraplaria ........................................3, 18

innocua, Menipea . _...________._.....1, 2, 7, 10; pi. 2

K

kenleyi, Figularia ............................................10,11

Kondo, Yoshio, cited ...................... .Ill

kondoi, Spiroporina ......................2, 6, 8, 14; pi. 4

laevigata, Smittea ......__________________________ 18

Ladd, H. S., Foreword .__. .__...._-III

laevigata, Smittia centralis ................. ....18

Page 

Lithothamnium ........................ ........ ..... E7

longicollis, Spiroporina __._ .._ -6,15

M 

macgillivrayi, Schizoporella ..... ....2, 17; pi. 5

Melson, William, cited .... V

Menipea ...............................................................2, 10

biaviculata ................................._._. ...... 10

crassa ........................................................... 10

elongata .... ... .........................~ ............ ...10

innocua .................................._1, 2, 7, 10; pi. 2

retrorsa ....................................................... 10

Morphology, deep-water species ..._.__ .... 7

N, O

Nellia . .....___._ .. .... 7

obesa, Tetraplaria ............................_ . ...4, 18

Ontogenetic differences, deep-water species . 7

Paleoenvironments __. ......_ _ . %

papillata, Bifaxaria ...................... ....... 11, 13, 14

Patsyella ....... ........................................ 2, 8

sp .. ... ..... .. . . ._ ._«; pi. 1

pedunculata, Tetraplaria ... .. ... ... -..... 4, 21

petila, Tetraplaria ...... ....... .... .___ _ 4, 18

Pollaploecium brevis ............. ............... . _.. . 3

gilbertensis .................................................. . 3

Poricellaria . . .... ..... ......... .... _ ....... ... 7

Porina . 14

gracilis .. .. . .......................................... ...14

tubulifera .. ..... ......................... IB

porosa, Chiastosetta ........................... 18

proditor, Tubitrabecularia ......................... .17

R 

References cited .. 22

Reteporellina .. - ..................................JZ, 6, 8, 17

sp - ........................................... ......^, 17; pi. 6

retrorsa, Menipea .. ...... 10

rugata, Bifaxaria . - .............. . 13, 14

Schizoporella .... ...... _ .......... _. 2, 17

macgillivrayi . ................. ........^, 17; pi. 5

Schizoporellidae ~_ ._.._ ._... .._._ . 17 

schreibersi, Cellaria .......................... ...._._ .18

Sclerodomidae _ _ ______ ... _ ... ..._ 11

Sclerodomus ..........................................5, 11, 12

Scrupocellariidae ___..._____.._ _...__... 8, 9 

Semihaswellia ... - 6

SerteUidae .. . ._.__.._. .. ..... 7, 17

simata, Tetraplaria ______________ ._.__2, 4, 19; pi. 7

Siphonicytara .......................................... 7, 16

Siphonicytaridae . . __.._- .16

Smittea laevigata .............. . ..................... 18

Smittia centralis laevigata .............................. ..18

spinigera, Beania ................................... ... . 9

Spiroporina . 2, 6, 14, 15

brevitubulata ............................................. 6, 15

deliqua ....._._~_ _ 2, 15; pi. 5

kondoi ~...................................J2, 6, 8, 14; pi. 4

longicollis . 6, 15

vertebralis ................ .. .. .- 14

Spiroporinidae 7,14
E26 INDEX

Page 

Stearms, H. T., quoted .._ .....EIII

Steganoporella .................................................... 7

striatum, Diplonotos ... .. ~ ............ .16

Tessaradoma ................................... .6, 8,16

submucronata, Bifaxaria ........._ . 4

Systematic paleontology ............................ ...... 8

T, U, V 

Tele-a-hiva ._. .. .... Ill

Temperature tolerances, Tongan Bryozoa ...... 2

Tessaradonm ... _ . . . .... . .. 2, 6, 15

distribution . .... 6

ontogenetic differences .....16

bifax ............................ ....... 2, 6, 7, 15; pi. 5

bipatens ........ ........ .................................. 6, 16

boreale ... ... .................................... 6, 15, 16

striatum ............................... ............... 6, 8, 16

Tetraplaria .... ................... 2, 3, 4, 6, 7, 18, 21, 22

astogenetic differences ... _ __ _ ______21

Page 

colony form ..... .... - _ _...... ..... ...E21

distribution .. . ____._..__ . _...................... 2

positional polymorphism .._................ ... -21

australis ..... ......... .. ..................... 4, 19, 21

caudifera .... ... ~ _. ....18

diehotoma .. ................... ..................B, 4, 18

gilbertensis ... . ....................IS

immersa ... . 3, 18

obesa .. . .. - ... . .. ...4, 18

pedunculate, ....-............................ .....A, 21

petila ..................................... 4, 18

simata ...........................................2, 4, IS; pi. 7

tuberculata ...... .. ..................................A, 18

turgida .... ................ ....... ....I, 2, 4, 21; pi. 7

veleroae ... _ .... ........_ . 3

ventricosa .. .. . -3, 4, 18, 22

sp . .. 4

Tetraplariidae ... . .... .... 18

Thalamoporella ........................................................ 1

Thermophilic genera _......__ .......... 2

Page 

species . ._._ ..._....... E6, 7

Todd, Ruth, age determinations 1

Triporula ........... ................................... 2, 6, 7, 11

biarmata ....................... ............. 2, 11; pi. 2

verrucosa .. - ..............................................A\

tuberculata, Tetraplaria .... .............. ._...4, 18

Tubiporella ..... _ . . 6

Tiibitrabecularia ............................................ 7, 16

clypeata .......................... .......I, 2, 7, 17; pi. 6

elevata ............. .. ......................................16

proditor .... ............... . ....... 17

tubulifera, Porina ~ ..... - .15

turgida, Tetraplaria . ............................I, 2, 4, SI

Ureeolipora .... ... ...... 11

Vaingana . . _. ....._............ .Ill, 1

veleroae, Tetraplaria . 3

ventricosa, Tetraplaria ............ ..........^, 4, 18, 22

verrucosa, Triporula ........... ._ . ... _ .11

vertebralis, Spiroporina ...... ......... .......... 14

U. S. GOVERNMENT PRINTING OFFICE : 1971 O - 440-746
PLATES 1-7

[Contact photographs of the plates in this report are available, at cost, from U.S. Geological 

Survey Library, Federal Center, Denver, Colorado 80225]
PLATE 1

[All figures X 50; specimens coated with ammonium chloride]

FIGURES 1, 2. Canda fossilis Waters (p. E9).

1. Frontal (a), basal (b), and left-frontal (c) views of unbranched zoarial fragment showing zooecia with 

prominent scutum attachments and vibracula with curved rostral channels and large rootle* foramina; 

USNM 169235, sample 2.

2. Frontal (a), basal (b), and right-lateral (c) views of dichotomous zoarial fragment; proximal zooecia 

have frontal avicularia; two most distal, broken zooecia are inner members of branches (Banner's 

(1923) zooecia F and G), meet above axillary zooecium (zooecium E) in basal view, and have basal 

vibracula; vibracula lie on interzooecial suture; USNM 169236, sample 2.

3. Patysellal sp. (p. E8).

Frontal views of zoarial fragment, showing ovicelled (a) and nonovicelled (b) zooecia; small occlusor-laminae 

are visible below distolateral portions of opesiae; USNM 169232, sample 1.

4. Cellaria cucullata MacGillivray (p. E8).

Frontal views of a zooecial series terminating at distal end of internode (a) and of one intersecting the joint 

(b); USNM 169233; sample 1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 1

CANDA, PATSYELLAt, AND CELLARIA
PLATE 2

[All figures X 50; specimens coated with ammonium chloride]

FIGURE 1. Figularial sp. (p. E10).

Frontal views of zoarial fragment, showing ovicelled (proximal zooecium, a) and nonovicelled (distal zooecium, 

a; b) zooecia; bases of spines (?) and costae (fused in right proximal zooecium shown in profile, b) and avicularia; USNM 169239, sample 2.

2. Menipea innocua Waters (p. E10).

Basal (a) and frontal (b) views of branched zoarial fragment showing long, laterally directed avicularia with 

proximal foramina placed on gymnocysts of biserially arranged zooecia; USNM 169238, sample 2.

3. Beania diademata, n. sp. (p. E9).

Basal (a) and frontal (b) views of zoarial fragment; small fenestrae show only basally among six connecting tubes 

for each zooecium; spine bases appear on mural rims, around distolateral margins, and on basal surfaces of 

zooecia; larger, unilateral (probable) base of avicularium shows on each zooecium just proximal to oral end; 

holotype, USNM 169234; sample 2.

4. Triporula aff. T. biarmata (Waters) (p. Ell).

Frontal view of encrusting zoarium showing irregularly arranged zooecia and apparent growing margin of colony 

(top of view) ; USNM 169240, sample 2.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 2

FIGULARIAt, MENIPEA, BEANIA, AND TRIPORULA
PLATE 3

[All figures X 50; specimens coated with ammonium chloride]

FIGURES 1-7. Bifaxaria diaphyota, n. sp. (p. E13).

1. Frontal view of zoarial fragment apparently from intermediate part of colony, showing median frontal 

furrow, bilaterally disposed frontal avicularia, and surface pitting; paratype, USNM 169246; 

sample 1.

2. Lateral view of zoarial fragment apparently from distal part of colony, showing interzooecial groove, 

lateral row of avicularia, striation-like pattern of fine pits, scattered frontal pores; holotype, USNM 

169245; sample 1.

3. Frontal view of zoarial fragment apparently from proximal part of colony, showing one pair of lateraloral avicularia (in middle orifice), numerous frontal avicularia and broken base of branch; paratype 

USNM 169247; sample 1.

4, 5. Lateral views of zoarial fragments apparently from proximal parts of colonies, showing broken bases 

of opposing branches and extreme development of frontal avicularia; paratypes, USNM 169248, 

169249; sample 1.

6, 7. Frontal views of zoarial fragments apparently from proximal parts of colonies, showing extreme development of frontal avicularia; paratypes, USNM 169250, 169251; sample 1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 3

BIFAXARIA
PLATE 4

[All figures X 50 : specimens coated with ammonium chloride]

FIGURES 1, 2. Spiroporina kondoi, n. sp. (p. E14).

1. Oblique frontal view of two zooecial series showing broken peristomes with proximolateral pores, spiramina, and frontal pores; holotype, USNM 169255, sample 1.

2. Frontal view of zoarial fragment preserving bifurcation; paratype, USNM 169257, sample 1. 

3. Chiastosellat sp. (p. E18).

Frontal view of encrusting zoarial fragment, showing one nearly complete zooecium and parts of four

others; that on right is possibly ovicelled; USNM 169275, sample 2. 

4, 5. Bifaxaria bryani, n. sp. (p. E12).

4. Frontal (a) and lateral (b) views of zoarial fragment apparently from distal part of colony, showing 

stem with broken unopposed branch, at base of which are lateral avicularia; holotype, USNM 169241, 

sample 2.

5. Lateral (a) and frontal (b) views of zoarial fragment apparently from proximal part of colony, showing 

approximately aligned lateral avicularia and swellings indicating possible ovicells; paratype, USNM 

169242, sample 2.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 4

BIFAXARIA, CHIASTOSELLAt., AND SPIROPORINA
PLATE 5

[All figures X 50; specimens coated with ammonium chloride]

FIGURES 1, 2. Spiroporina deliqua, n. sp. (p. E15).

1. Frontal (a) and distal (b) views of abraded zoarial fragment preserving growing tip; paratype, USNM 

169261; sample 1.

2. Frontal view of parts of four whorls of zooecia separated by shallow grooves with V-shaped lobes directed 

proximally between peristomes; frontal avicularium in one proximal lobe; holotype, USNM 169260, 

sample 1. 

3. Schizoporella aff. S, macgillivrayi Canu and Bassler (p. E17).

Frontal view of subcylindrical zoarial fragment; USNM 169273, sample 1. 

4, 5. Tessaradoma bifax, n. sp. (p. E15).

4. Frontal (a) and lateral (b) views of zoarial fragment apparently from proximal part of colony, showing nonsinuate secondary orifices and imperforate frontal surfaces; paratype, USNM 169264, 

sample 1.

5. Lateral (a) and frontal (b) views of zoarial fragment apparently from distal part of colony, showing 

sinuate secondary orifices, apparently marginal pores, and lateral avicularia; holotype, USNM 169263, 

sample 2.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 5

SPIROPORINA, SCHIZOPORELLA, AND TESSARADOMA
PLATE 6

[All figures X 50; specimens coated with ammonium chloride]

FIGURES 1, 3, 4. Reteporellina1! sp. (p. E17).

1. Frontal (a) and basal (b) views of quadriserial, ovicelled zoarial fragment, showing broken ovicells, 

frontal avicularia, and nearly smooth basal surface; USNM 169268, sample 1.

3. Basal view of nonovicelled, quadriserial zoarial fragment, showing two bifurcations; USNM 169269, 

sample 2.

4. Frontal (a) and basal (b) views of nonovicelled, biserial zoarial fragment, showing biperforateappearing secondary orifices, tuberculate basal surface with one transverse ridge, and two basal 

avicularia in axils; USNM 169270, sample 2. 

2. Tubitrabecularia clypeata (Waters) (p. E17).

Frontal view of zoarial fragments showing elongate zooecia divided at tubular ascopore collar into subequal proximal and peristomal areas; faint longitudinal ridge on peristome; and paired lateral-oral 

avicularia with complete crossbars; USNM 169266, sample 1.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 6

RETEPORELLINA? AND TUBITRABECULARIA
PLATE 7

[All figures X 50; specimens coated with ammonium chloride]

FIGURES 1, 4, 5. Tetraplariasimata,n.sp. (p. E19).

1. Frontal views of zooecia of first, third, and fifth pairs (a) and of second and fourth pairs (b) of 

complete, abraded internode; paratype, USNM 169277, sample 2.

4. Frontal views of zooecia of first, third, and fifth pairs (a) and of second and fourth pairs (b) of 

complete, ovicelled internode; holotype, USNM 169276, sample 2.

5. Frontal views of zooecia of first, third, and fifth pairs (a) and of second and fourth pairs (b) of

complete internode; paratype, USNM 169278, sample 1. 

2, 3. Tetraplaria cf. T. turgida Tewari and Srivastava (p. E21).

2. Frontal views of zooecia of second and fourth pairs (a) and of first, third, and fifth pairs (b) of 

complete, ovicelled internode; USNM 169280, sample 2.

3. Frontal views of zooecia of second pair (a) and of first and third pairs (b) of nearly complete internode; USNM 169281, sample 2.
GEOLOGICAL SURVEY PROFESSIONAL PAPER 640-E PLATE 7

TETRAPLARIA