bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlative Fine Structural, Behavioral, and Histochemical Analysis of Ascidian Blood Cells
Authors: Fuke Masako , Fukumoto Makoto
Published: April 2010

Abstract The blood cells of a solitary ascidian, Halocynthia roretzi, were examined by electron microscopy (EM) with reference to their appearance by light microscopy (LM). In addition, their movement and stainability by vital dyes was observed by phase‐contrast microscopy, and their stainability by Giemsa was also examined. Nine cell types were recognized: vacuolated cells, hyaline amoebocytes, small amoebocytes, granular amoebocytes, macrogranular cells, globular cells, lymphocyte‐like cells, large basophilic cells and large granular cells. Vacuolated cells were found to possess various numbers of vacuoles containing strongly electron‐dense materials and could be divided into at least three subgroups. Granular amoebocytes contained microfilaments and many granules of uniform size. Hyaline amoebocytes and small amoebocytes seemed to be specialized as phagocytes. Macrogranular cells and globular cells were not well characterized. In the blood of adult individuals, hemoblasts were rarely found, although lymphocyte‐like cells were present. Each of two large cells, large basophilic cells and large granular cells, possessed novel granules or vacuoles, whose functions remain to be elucidated. The possible functions and relationships of these cells among various ascidian species are discussed.
Functional Architecture of the Vomeronasal Organ of the Frog (Genus Rana)
Authors: Døving Kjell B. , Trotier Didier , Rosin Jean‐François , Holley André
Published: April 2010

Abstract The vomeronasal organ in the frog, genus Rana, is composed of three interconnected cavities; superior, middle and inferior, which are separated from and anterior to the principal olfactory cavity. The superior cavity is found just underneath the external naris and forms a vestibule both for the principal olfactory organ and the vomeronasal organ. The vomeronasal sensory epithelium is located in the medial region of the inferior cavity and contains ciliated cells and microvillous receptor cells. Inspection of microscopic sections of frogs that had been swimming in fluorescent colorants revealed fluorescence on the surface of the vomeronasal organ, but not on that of the olfactory organ. Observations in vivo show that water enters via the external naris by two fissures, one on each side of the movable nasal lid, passes the middle cavity to flow via the sensory epithelium of the inferior cavity. The design of the frog nose makes it possible for this amphibious animal to sample the chemical composition of its environment; above water the frog can inhale air and expose its olfactory organ to volatile substances; in water the vomeronasal organ samples water‐borne substances. These new findings are discussed in relation to the air/water interface and the position of the amphibians in the evolution of terrestrial vertebrates.
Serotonin‐containing Cells in the Nervous System and Other Tissues During Ontogeny of a Lancelet, Branchiostoma floridae
Authors: Holland Nicholas D. , Holland Linda Z.
Published: April 2010

Abstract Serotonin‐containing cells are described by immunohistochemistry throughout lancelet ontogeny. Such cells are first detected in the 2‐day larva: these are (1) enterochromaffin cells in the inner epithelium of the gut and (2) anterior serotonergic neurons at the rostral end of the nerve cord. In the 6‐day larva, relatively low levels of serotonin appear in ventro‐lateral perikarya and cell processes of intraspinal serotonergic neurons scattered along the nerve cord. In the 18‐day (early metamorphic) larva, antero‐lateral serotonergic neurons are detected near the rostral end of the nerve cord as two small, bilateral clusters of perikarya with axons that descend the nerve cord; at later developmental stages, these axons extend almost to the posterior end of the body. In the 21‐day (mid‐metamorphic) larva, serotonin can no longer be detected in the anterior serotonergic neurons, but serotonin‐containing cells are found subjacent to the inner epithelium of the digestive caecum and in the peribranchial epithelium covering the primary gill bars. In the discussion, we suggest that the anterior serotonergic neurons may play a role in larval photoreception and that the antero‐lateral serotonergic neurons may be homologous to vertebrate hindbrain neurons with axons descending the spinal cord to modulate undulation (if this homology is valid, the anterior limit of the lancelet hindbrain would be roughly 100 μm behind the rostral tip of the nerve cord).
F‐Actin and Tubulin During Spermatogenesis in Gamasid Mites (Acari: Parasitina)
Authors: Witaliñski W. , Dallai R.
Published: April 2010

Abstract F‐actin and tubulin behaviour was investigated using fluorescence probes and electron microscopy in the course of spermatogenesis in two gamasid mites, Porrhostaspis lunulata Müller (Parasitidae) and Pergamasus truatellus Athias‐Henriot (Pergamasidae). In spermatogonia and primary spermatocytes of both species, the proteins were localized mainly in the intercellular bridges and, in lesser quantities, in the cytoplasm. Overall, actin was present along the plasma‐lemmal contact sites of the gonial cells.

At the beginning of spermatid elongation, actin could be detected in two regions: in perinuclear cytoplasm and under the plasmalemma. Subplasmalemmal actin, visible as threads running along acrosome‐adhering protrusions of the nuclear envelope, is supposedly located within the electron‐dense material filling the subacrosomal gap. Tubulin was found on both sides of each actin thread; its location was consistent with two sets of microtubules adhering to the inner acrosomal membrane. Their involvement in acrosome shaping is suggested.

As spermatid elongation terminated, the previous pattern of proteins disappeared. In Pergamasus, however, actin emerged briefly near the centrifugal ends of spermatids (granular bodies zone).

In spermatocyte‐containing cysts, actin and tubulin fluorescence (more pronounced in Porrhostaspis) was associated with intercellular junctions between the cyst cells. In both species, diffuse actin fluorescence was also detected in the cytoplasm of cyst cells assembling elongated spermatids; the reaction was intensified at the end of the elongation process, when the cytoplasm of cyst cells aggregated around the centripetal ends of spermatids.
Morphometry of the Gill Respiratory Area in Comephorus dybowskii and Some Other Endemic Cottoidei of Lake Baikal
Authors: Jakubowski Michał
Published: April 2010

Abstract Morphometric investigations of the gill apparatus in the small golomyanka, Comephorus dybowskii, revealed a unique structure and a very small gill respiratory area (GRSA) compared with other endemic Cottoidei of Lake Baikal: from 5.5 to about 7 times smaller than in the pelagic waterside sculpins. Cottocomephorus grewingki and C. inermis, and about 3 times smaller than in groundling deep‐water Cotinella boulengeri. This is an extremely small GRSA considering no accessory respiratory organs are present. Scanning electron microscopic observations revealed numerous chloride cells in the epithelium of golomyanka gill lamellae but not in the sculpin lamellae. Chloride cells probably restrict gas exchange in the lamellae considerably. The results suggest that golomyankas have a small oxygen requirement.
Ultrastructure of the Accessory Glands in Female Genitalia of Pholcus phalangioides(Fuesslin, 1775) (Pholcidae; Araneae)
Authors: Uhl Gabriele
Published: April 2010

Pholcus phalangioidesdoes not possess receptacular seminis. The uterus externus (genital cavity) itself functions as a sperm storage structure. Two accessory glands are situated in the dorsal part of the uterus externus; they discharge their secretory product into the genital cavity.

The secretion is considered to serve primarily as a matrix for sperm storage, i.e. to keep the spermatozoa in a fixed position.

The accessory glands consist of numerous glandular units, each being composed of four cells: two secretory cells are always joined and surrounded twice by an inner and an outer envelope cell. Both envelope cells take part in forming a cuticular ductule that leads from the secretory cells to the pore plates of the uterus externus. The inner envelope cell produces the proximal part of the canal close to the microvilli of the secretory cells, whereas the outer envelope cell produces the distal part of the canal leading to the pore plate. Close to the pore the latter exhibits prominent microvilli that might indicate additional secretory activity.
The Fine Structure of Trichobothria in Moss Mites with Special Emphasis onAcrogalumna longipluma(Berlese, 1904) (Oribatida, Acari, Arachnida)
Authors: Alberti Gerd , Moreno Ana I. , Kratzmann Markus
Published: April 2010

Using SEM and TEM techniques, the trichobothria ofAcrogalumna longipluma(Galumnidae, Pterogasterina) were studied in relation to a variety of other moss mites. Each sensillum is composed of a mostly solid bothridial seta and a very complex socket, the bothridium. The setal base bends sharply as it passes through the six chambers of the bothridium, which are arranged in an S‐shaped configuration. The proximal end of the seta is an elongated oval and inserted into a thin socket membrane provided with radiating suspension fibres. This peculiar shape of the setal base proper and probably also the existence of connecting pieces are assumed to provide directionality to the sensillum. Two differently shaped tubular bodies are found under the setal base, of which only one is in contact with the seta. The tubular bodies are surrounded by peculiar ‘dense tubes’, i.e. derivatives of the dendritic sheath. The rather thick, outer dendritic segments curve through an extensive receptor lymph cavity and terminate with ciliary regions. The inner dendritic segments are only short. Perikarya and axons as well as the enveloping cells do not show any peculiarities. The trichobothria of moss mites most probably represent vibration receptors reacting to substrate and/or air‐borne stimuli. The variety of shapes and the complexity, which is not found to this extent in any other arthropod group, are discussed in relation to ecophysiological demands.
Matrix Heterogeneity in the Radular Teeth of the Chiton Acanthopleura hirtosa
Authors: Evans L. A. , Macey D. J. , Webb J.
Published: April 2010

The structure and organization of the organic matrix of the cusps of the major lateral teeth of the chiton Acanthopleura hirtosahave been examined using conventional light and transmission electron microscopy techniques and by using the protein ferritin as an ultrastructural probe. The results show major structural differences in the organic matrix between the surface layers of the anterior (calcified) region and the posterior (magnetite‐mineralized) region and their respective underlying regions. In addition, the central (lepidocrocite‐mineralized) region of the tooth has been examined and shown to consist of bundles of fibres arranged such that they display a tightly interwoven pattern. It is suggested that while the structural organization of surface fibres readily permits the passage of ions required for mineralization, the architecturally discrete distribution of biominerals found in mature chiton teeth is due mostly to spatial delineation of the tooth by matrix macromolecules in the central region of the tooth.
Spermiogenesis in a Scutariellid (Platyhelminthes)
Authors: Iomini Carlo , Ferraguti Marco , Melone Giulio , Justine Jean‐Lou
Published: April 2010

Spermiogenesis and spermatozoa were studied by transmission and scanning electron microscopy in Troglocaridicolasp., a scutariellid epizoic on a cavernicolous freshwater shrimp. Spermiogenesis involves elongation of the spermatid in which the nucleus elongates, but remains close to the common cytoplasmic mass. Flagella first grow in opposite direction and at a right angle to the cytoplasmic shaft, and centrioles show associate structures. Later, the two centrioles rotate and the flagella emerge parallel, but still perpendicular to the shaft. An apical process elongates at the extremity of the spermatid shaft. The spermatozoon shows active flagellar beating and undulations of the sperm body. The spermatozoon comprises an anterior ‘corkscrew’ region, the flagellar insertion region, a cytoplasmic region and a posterior nuclear region. The corkscrew contains an electron dense structure, not membrane‐bound, originating from the apical process of the spermatid. The flagella show the 9+‘1’ pattern, usual in Platyhelminthes. The cytoplasmic and nuclear regions show a cortical row of about 50 twisted longitudinal microtubules surrounding a row of electron dense, and not membrane‐bound, 25‐nm granules. These granules are original structures and seem to be known only in a few Platyhelminthes species in which a non‐flagellar movement of the spermatozoon occurs. Thus, it is hypothesised that the 25‐nm granules play a role in cellular motility. Sperm ultrastructure in Troglocaridicolashows major differences to that in the temnocephalids. It is therefore concluded that the phylogenetic position of the scutariellids within the Temnocephalidea should be reinvestigated.
Morphology of the Luminous Organ of the Squid Loligo duvaucelid'Orbigny, 1839
Authors: Pringgenies Delianis , Jørgensen Jørgen Mørup
Published: April 2010

The present paper deals with the morphology of the luminous organ of the squid Loligo duvauceli, caught in the sea off Indonesia and Thailand. Two luminous organs are situated on the ventral surface of the ink sac, near the anus. Each organ consists of a luminous sac divided into numerous discrete chambers containing bacteria. On the ventral side the organ is bordered by a lens‐like structure, consisting of muscle cells. On the remaining sides the bacterial chambers are limited by a cup‐shaped reflector layer with numerous parallel lamellae. The reflector separates the bacterial chamber from the ink sac. A ciliated channel connects the interior of the bacterial chamber with the mantle cavity.
Scanning Electron Microscopy of Mouth Appendages in Six Species of Barnacles (Crustacea Cirripedia Thoracica)
Authors: Høeg Jens. T. , Karnick Elisabeth S. , Frølander Amy
Published: April 2010

The morphology and setation of mouth appendages (trophi) are investigated with scanning electron microscopy in the balanomorph barnacles Semibalanus balanoides, Balanus balanusand B. nubilusand in the pedunculate barnacles Pollicipes polymerus, P. cornucopiaand Lepas anatifera.It is difficult to uphold a clearcut distinction between denticles and setae and several types of setae also intergrade with each other. The trophi of Pollicipes polymerusand P. cornucopiahave the most ‘generalized’ morphology. The palps of Pollicipesand L. anatiferaare simpler than those in balanomorphs and carry a single type of seta. In L. anatiferathe mandibles and maxillules are adapted to a semi‐predatory feeding habit by carrying large, pointed teeth, but this species lacks the foliate‐serrate setae which populate the palps in the other species studied. Compared with Pollicipesand Lepas, the three balanomorphs have palps with a complex setation. The trophi in S. balanoidesdiffer from the two species of Balanusin numerous features of setation and denticulation, notably in having the palps populated by plumodenticulate setae homologous to purely denticulated types in Balanus.It is suggested that SEM studies of barnacle trophi will provide characters of use in estimating phylogeny.
The Evolutionary Origin and Homologues of the Supracochlear Lamina: a Contribution to our Knowledge of Mammalian Ancestry
Authors: Bjerring Hans C.
Published: April 2010

In cetaceans, each otic capsule is bound anteriorly to the remainder of the endocranium by an aliform structure called the supracochlear lamina. This lamina has been established here as the homologue of the sphenocochlear commissure of other mammals. Most researchers believe that these two structures arose within mammals. However, a comparative study involving data from both extant and extinct craniates suggests that the supracochlear lamina and the sphenocochlear commissure have a long premammalian history. The conclusion is that the lower of the two pharyngeal segments at the upper end of the mandibular branchial arch first became incorporated in the endocranium, constituting the cartilago trabecularis in the embryos of jawed craniates. The distal, or posterior, extremity of the trabecular cartilage projected outwardly to form the basitrabecular process. This process, which when ossified is called the processus basipterygoideus, functioned as a jaw support. Later, one more jaw support, termed the basivincular, evolved immediately in front of the basipterygoid process. Both these supports for the upper jaw existed in the piscine forerunners of the tetrapods. Subsequently, in the lineages leading to mammals, the basivincular jaw support became the processus alaris to which is attached an upper jaw endoskeletal remnant, called the ala temporalis. The basipterygoid jaw support, however, vanished as a consequence of the evolution of an exoskeletal joint system for the jaws of mammals. Yet the basipterygoid process persisted and as the sphenocochlear commissure or the supracochlear lamina assumed the new function of supporting the cochlear part of the auditory capsule.
Comparative Morphology and Function of Hepatic Caeca in Four Enteropneusts
Authors: Bridges Todd S. , Woodwick Keith H.
Published: April 2010

A morphological and functional study was made of the hepatic region in four enteropneust hemichordates: Schizocardiumsp., Ptychodera flava, Ptychodera bahamensis, and an undescribed ptychoderid from Maui, Hawaii, using light and electron microscopy. The hepatic region of these enteropneusts, as well as others, is characterized by a brown‐green color and the presence of numerous caeca which represent dorsal extensions of the gut. These caeca extend above the dorsal surface of the worm and are organized into bilateral rows. Species‐specific differences were noted in the organizational pattern of the sacculations within rows and the morphology and histology of individual sacculations. Numerous brown‐green vesicles were discovered in both the epithelial cells and lumen of sacculations. Transmission electron microscopy revealed these bodies to be heterophagic vacuoles and residual bodies. Morphological evidence suggests that hepatic caeca are involved in intracellular digestion. Once endocytosed food particles are packaged as heterophagic vacuoles, and digestion has been completed, the residual bodies are packaged together and exuded from the cell in a spherule of cytoplasm.
The Spermatozoon of Brachionus plicatilis(Rotifera, Monogononta) With Some Notes on Sperm Ultrastructure in Rotifera
Authors: Melone Giulio , Ferraguti Marco
Published: April 2010

The spermatozoon of B. plicatilisis a thread–like cell with an anterior flagellar portion and a posterior cell body. The flagellum has a lateral ‘undulating membrane’, containing a folded longitudinal cisterna and an axoneme. The basal body of the axoneme is at the anterior tip. The axoneme lacks outer dynein arms and extends through the entire flagellar region and most of the cell body. The main portion of the flagellum and of the cell body contains a series of vesicles with tightly packed tubules that may serve as a cytoskeleton. The cell body contains a partly condensed nucleus, several mitochondria and some cytoplasm. Some elongated mitochondria are arranged in the postnuclear region. When the spermatozoon moves, the undulations propagate from the basal body at the flagellar tip. Late spermatids can be recognized by the nucleus and the flagellum being coiled and enclosed within a common cell membrane. As in other rotifers, there are cigar–like cell products (‘rods’) in the testes. The general organization of the cell, including the absence of an evident acrosome, resembles that of the other known monogonont sperm types.
Relationship of Homolidae and Dromiidae: Evidence from Spermatozoal Ultrastructure (Crustacea, Decapoda)
Authors: Guinot D. , Jamieson B. G. M. , de Forges B. Richer
Published: April 2010

Abstract The homolid spermatozoon, as exemplified by Homolasp., Paromolasp. and Paromola petterdi, differs markedly from spermatozoa of crabs of the Heterotremata–Thoracotremata assemblage but agrees with the sperm of dromiids, in the strongly anteroposteriorly depressed acrosome (apomorphy?) and the capitate form of the perforatorium (a major synapomorphy seen nowhere else in the Crustacea). These similarities support inclusion of the Dromiidae and Homolidae in a single grouping, the Podotremata. The homolid perforatorium differs from that of dromiids in the autapomorphic spiked–wheel form of the anterior expansion. Homolid spermatozoa show nuclear arms symplesiomorphic of all investigated crabs (small or questionably sometimes absent in Dromiidae), and corresponding loss of purely microtubular arms seen in other reptants. Homolid sperm agree with those of dromiids (synapomorphy?), raninids, higher heterotremes and thoracotremes (homoplasies?) but differ from lower heterotremes, in lacking microtubules in the nuclear arms. A posterior median process of the nucleus in homolids, not seen in dromiids, is shared with anomurans and lower heterotremes. No features in the ultrastructure of homolid or dromiid sperm have been detected which associate them exclusively with either the Raninidae or the heterotreme and thoracotreme Brachyura.
Ultrastructure of the Male Accessory Glands and Sperm Ducts of Cylindrotaenia hickmani(Cestoda, Cyclophyllidea)
Authors: Jones Malcolm K.
Published: April 2010

Abstract The ultrastructure of unicellular accessory glands (= prostate glands) and external male ducts of the cestode Cylindrotaenia hickmaniare described. Accessory glands open into the lumen of the external common sperm duct (= external vas deferens). The gland cells contain abundant endoplasmic reticulum, Golgi bodies and secretory bodies, and have elongate necks that pierce the apical cytoplasm of the duct. Cell contact with the apical cytoplasm of the sperm duct is mediated by septate desmosomes. Accessory glands secrete spherical particles, with a diameter of approximately 70 nm, that adhere to spermatozoa. The roles of these accessory glands may relate to activity of the sperm or development of the female system after insemination. Paired sperm ducts arise from testes, and unite to form a common sperm duct. Each duct consists of a tubular anucleate cytoplasmic region which is supported by nucleated cytons that lie sunken in the parenchyma. The apical cytoplasm of the paired sperm ducts (= vasa efferentia) possesses apical microvilli and abundant mitochondria, but few other cytoplasmic features. The apical cytoplasm of the common sperm duct possesses sparse apical microvilli and numerous electronlucent vesicles. The male gonoducts form an elongate syncytium which is markedly polarized along the length of the ducts. The ducts also display apical–basal polarity in that sunken nucleated cytons support the apical cytoplasm which in turn has distinct basal and apical domains.
The Structure of the Spermatozoon of the Japanese Quail, Coturnix coturnix L., var. japonica
Authors: Woolley D. M.
Published: April 2010

The spermatozoa of the Japanese quail conform, in their general ‘sauropsid’ plan, to that of other non‐passerine birds. They are notable, however, in that the flagellum is very elongated (208 μm) and carries approximately 2,500 mitochondria in an extensive midpiece. Ultrastructurally, the acrosome and acrosome‐nucleus junction is exactly as reported for other galliform birds. The neck region contains two centrioles arranged almost in‐line; this unusual layout apparently occurs also in guinea fowl sperm. At the tip of the axoneme, beyond the termination of the central pair microtubules, is a structure—the tip granule—previously recognized in sperm of the domestic fowl. Trypsin digestion splits the axonemal cylinder, and the doublets then spiralize. This response has been reported before, in the sperm tails of other avian species.
Classification, Based on Autonomous Fluorescence, of the Blood Cells of Several Ascidians that Contain High Levels of Vanadium
Authors: Wuchiyama Junko , Michibata Hitoshi
Published: April 2010

Ascidians are known to have the unique ability to accumulate vanadium in their blood cells. Classification of the various types of blood is, however, the subject of some controversy. In the present study we found that the various types of blood cell can be classified on the basis of their autonomous fluorescence upon excitation with blue‐violet light. This method was of particular practical value in the classification of the vacuolated cells that account for about 80% of the total population of cells and are distinguished by their ability to accumulate vanadium.
The Parietal Problem: How to Cut This Gordian Knot?
Authors: Bjerring Hans C.
Published: April 2010

Although no one has disputed that the piscine progenitors of the tetrapods have a homologue of the human parietal bone, opinions differ as to where in the skull roof this homologue is located. One view holds it to be either of two interorbital bones that together surround the foramen neuroepiphysium (and the so‐called pineal plates); another, that it is each of the two mesial bones which comes next in order, behind the orbital cavities. Both of these views are untenable because neither of the proposed bones has proved to be amenable to conversion to the parietal bone of man. In seeking a solution to this issue thoughts turn to the tentorium cerebelli, whose topographic relationships and comparative morphology place it in the key position as a plausible derivative of the posterior half of the cranium of the tetrapod forerunners. Following this line of reasoning, it can be suggested that the tentorial exoskeleton, here called the pluteal bones, originally was situated in the dermis superjacent to the synotic tectum. In early therian phylogeny, these skull bones were covered by the backwardly expanding cerebral hemispheres which, concomitantly, became overgrown and thus protected by epiotic exoskeleton. It follows that the likely homologues of the human parietal bones are those parts of the skull roof of the piscine progenitors of the tetrapods that lie dorsolateral to the otic capsules.
A Comparative Structural Study on Bacterial Symbioses of Caribbean Gutless Tubificidae (Annelida, Oligochaeta)
Authors: Giere Olav , Nieser Christiane , Windoffer Reinhard , Erséus Christer
Published: April 2010

The bacterial symbiosis in 13 different species of the gutless phallodriline genera Inanidrilus and Olavius (Tubificidae, Oligochaeta) from Carrie Bow Cay (Belize), Florida and Bermuda is structurally compared. The result is an essentially consistent symbiotic pattern regarding the position and ultrastructural design of the prokaryotic partners and their integration in the anatomy of the animal hosts. Based on numerous micrographs, it is calculated that the endobacteria comprise about 25% of the host's volume. This corresponds to at least 0.6 × 106 bacterial cells per worm of (fixed) 6 mm length, a figure that underlines the high nutritive importance of the bacteria in this symbiotic association. This importance is also endorsed by the percentage of bacteria in digestion (on average 8–10%, up to 24%) by the phagocytotic epidermal cells of the host. The symbiosis always involves two different morphological types of bacteria, apparently without intermediate stages. Detailed biometrical analyses demonstrate the significantly different size ranges of the two morphotypes, even though in two of the species, the normally rod‐shaped Type S‐bacteria are much longer than usual. About 1% of the larger, oval ‘Type L’ is regularly found in division; in some sections, this value can reach 11%. Formation of sulfur‐containing globules in this type was proven by histochemical analysis. The trophic relevance of the symbiosis is considered. Zoogeographical and evolutionary implications of the observed consistency in the symbiotic pattern in all the species studied are discussed.
Copulatory Mechanism in Holocnemus pluchei and Pholcus opilionoides, With Notes on Male Cheliceral Apophyses and Stridulatory Organs in Pholcidae (Araneae)
Authors: Huber Bernhard A.
Published: April 2010

Huber, B. A. 1994. Copulatory mechanism in Holocnemus pluchei and Pholcus opilionoides, with notes on male cheliceral apophyses and stridulatory organs in Pholcidae (Araneae).—Acta Zoologica (Stockholm) 76: 291–300.

The pholcid spiders Holocnemus pluchei (Scopoli, 1763) and Pholcus opilionoides (Schrank, 1781) are investigated with respect to functional morphology of their genital organs using freeze‐fixation of spiders during copula in liquid nitrogen and subsequent preparation of histological serial sections of the copulatory organs in functional contact. Special attention is paid to the mode of male pedipalpal arrestation before copulation, which is achieved in two quite different ways: in Pholcus by contact of the lateral cheliceral apophysis with the pedipalpal trochanter‐apophysis, in Holocnemus by locking the pedipalpal trochanter between chelicera and pedipalpal coxa. The condition in Pholcus is considered to be apomorphic and to present a synapomorphy of about a dozen genera for which the name “Pholcus‐group” is proposed. The stridulatory apparatus of Holocnemus pluchei is described, its biological significance discussed and an overview of accounts on stridulation in Pholcidae given.
Fusion of Otoconia: a Stage in the Development of the Otolith in the Evolution of Fishes
Authors: Gauldie R. W.
Published: April 2010

Abstract The rigid, polycrystalline otolith of teleosts is a side‐branch of the general evolution of endolymphatic otoconia that extends from the sharks and rays to the higher vertebrates including man. The transition from the otoconial mass found in the endolymphatic sac of sharks and rays to the rigid polycrystalline otolith of teleosts probably occurred by progressive fusion of otoconia from a loose aggregate to a semi‐rigid mass. Traces of the primitive fused otoconia type of otolith still occur in the otherwise polycrystalline otoliths of some teleosts, and a few species of fish retain otoliths that are probably similar to the primitive fused otoconia type of otolith. The morphology of the fusion of otoconia varies according to the polymorph of calcium carbonate that is involved, as well as the particular crystal habit of the polymorph. Analyses of the size distributions of the polymorph‐specific morphologies and crystal structure of otoconia suggest that three physical chemical processes, Ostwald ripening, Keith‐Padden spherulitic growth and carbonate cementation are significant in the chemistry of fusion of otoconia in the evolution of the aragonite teleost otolith. Predictions of otoconia growth rate from the theory of Ostwald ripening can be compared with predictions from the Keith‐Padden theory of spherulitic growth.
Ascidian Larvae: The Role of Test Cells in Preventing Hydrophobicity
Authors: Cloney Richard A. , Hansson Lars Johan
Published: April 2010

Abstract Ascidian test cells co‐differentiate on the surface of each ovarian oocyte beneath the vitelline coat. They become vacuolated and later occupy the perivitelline compartment of each egg and embryo. In some species, their vacuoles contain submicroscopic granules or filaments called ‘ornaments’ and acidic glycosaminoglycans. These test cells deposit their products on the surface of the larval tunic in late embryogenesis. In these species, the test cells are lost at hatching. In other species, the test cell vacuoles contain acidic glycosaminoglycans, but no ornaments. In these species, the test cells attach to the larval tunic and probably secrete acidic glycosaminoglycans. We deprived the embryos of seven species of ascidians of their test cells and vitelline coats during midembryogenesis. After completing their development, the larvae of both kinds of species were hydrophobic. They easily become trapped on the surface of sea water in cultures. Normal larvae (controls), bearing test cell secretions, are hydrophilic and never become trapped. We infer that negatively charged secretions of the test cells make normal larvae hydrophilic. Some molgulids with direct development have no test cells, no fins and no swimming larva. We reason that the test cells of these species may have been lost during evolution because they no longer had an important role in preventing hydrophobicity.
Immunocytochemical Evidence of a Tubulin Reserve at the Tip of Growing Flagella in Spermatogenesis of the Mediterranean Mealmoth, Ephestia kuehniella Z. (Pyralidae, Lepidoptera, Insecta)
Authors: Wolf Klaus Werner
Published: April 2010

Abstract The distal swellings of growing flagella in spermatocytes of Ephestia kuehniella Z. contain dense material associated with the ends of axonemal microtubules. In order to define the nature of this material, spermatocytes were lysed under microtubule‐stabilizing conditions, spun onto cover‐slips, probed with an antibody against β‐tubulin and processed for indirect immunofluorescence. Whereas the dense material was lost from the cells when untreated spermatocytes were used, a block of stained material was visible in cold‐treated spermatocytes. Most probably, cold‐treatment alters the dense material and guarantees its survival during preparation of the cells for anti‐tubulin immunofluorescence. The positive reaction with the antibody indicates the presence of β‐tubulin. Flagellar outgrowth in spermatogenesis of the moth starts in late prophase I and continues throughout both meiotic divisions. Therefore, spindles and flagella compete for tubulin monomers. A tubulin reserve, deposited early in development at the elongating tip of axonemes, may ensure their uninterrupted growth, independent of tubulin‐consuming cytoplasmic events. In order to test this hypothesis, flagellar outgrowth was studied in the spermatocytes of a long‐horned beetle, Agapanthia villosoviridescens de Geer (Cerambycidae, Coleoptera) using electron microscopy. In this species, flagella begin to elongate only in telophase II, when the second meiotic spindle is just disassembling. The absence of dense material at the tip of flagellar stubs in the beetle corroborates the hypothesis formulated above.
Flagellar Axonemes with 10 Microtubular Doublets in Spermatozoa from Gall‐midges (Diptera, Cecidomyiidae)
Authors: Dallai Romano , Afzelius Björn A. , Mamaev Boris
Published: April 2010

Abstract The spermatozoa of some gall‐midges (Cecidomyiidae, Lestremiinae), belonging to the tribe Micromyini, were seen to have an axoneme that consists of 10, instead of nine, microtubular doublets surrounding a central cylinder. In some related species within the same tribe the axoneme was found to contain a similar cylinder but to have nine doublets, as in typical flagella, or to have nine doublets and no central structure. These three types of axonemes can be given the shorthand designations “10+cyl”,“9+cyl”, and “9+0”. The tribe Lestremiini is characterized by a giant axoneme having 150 doublets in two rows reversely oriented. Other characteristics of examined spermatozoa are the electron density of the B‐tubules of the axoneme, a feature shared by all members of the subfamily Lestremiinae, and the presence of a prominent cytoplasmic droplet containing numerous, regularly spaced microtubules, which is shared by all Micromyidi. These axonemal models are discussed from a phylogenetic point of view.
Structural Organisation of the Cusps of the Radular Teeth of the Chiton Plaxiphora albida
Authors: Macey D. J. , Brooker L. R. , Webb J. , Pierre T. G. St.
Published: April 2010

Abstract The structure, morphology and organisation of the cusps of the major lateral radula teeth of the chiton Plaxiphora albida have been examined using light, transmission and scanning electron microscopy, together with energy dispersive X‐ray analysis and Mössbauer spectroscopy. In this chiton species, both the anterior and posterior surfaces of the major lateral teeth are composed of magnetite, which is indicated to be non‐stoichiometric and associated with some maghemite, together with small amounts of phosphorus and silicon. This outer layer surrounds an inner core region of the tooth, which only reaches the surface through a small window zone on the anterior surface and which contains large amounts of iron and phosphorus presumably in the form of iron(III) phosphate. The organic matrix, on which the teeth are constructed, consists of a zone of densely packed fine fibres at the surface of the tooth, underlain by larger fibres which become sparser deeper into the cusp. The core region is characterized by the presence of densely packed short fibres. In contrast to the situation found in most other species of chiton, large fibres of the organic matrix extend throughout the region of magnetite mineralization, leading to the suggestion that the matrix exerts more control over the mineralization of magnetite than has previously been thought.
Anatomy of Laevipilina antarctica, a Monoplacophoran Limpet (Mollusca) from Antarctic Waters
Authors: Schaefer Kurt , Haszprunar Gerhard
Published: April 2010

Abstract The anatomy of the neopilinid limpet Laevipilina antarctica is described on the basis of reconstructions of semithin serial section. In general the anatomy of this small (3.2 mm) species resembles those of Neopilina galatheae (37 mm) and Vema ewingi (27 mm); small differences occur in the alimentary tract. Corrections of the original descriptions of neopilinid anatomy concern the structure of the mantle margin, the presence and interpretation of cephalic appendages, and details of the nervous system. The excretory organs are clearly separated from each other and there is no connection with the pericardium. The neopilinid ctenidia are considered as ventilatory rather than respiratory organs.

These corrections and clarifications of the neopilinid anatomy provide an improved database for discussion on monoplacophoran affinities. In contrast to popular statements about “living fossils”, the extant Tryblidiida (Neopilinoidea) are regarded as a considerably modified and specialized early conchiferan branch.
Nervous System of the Larva of the Ascidian Molgula citrina(Alder and Hancock, 1848)
Authors: Vorontsova M. N. , Nezlin L. P. , Meinertzhagen I. A.
Published: April 2010

Features of the nervous system, especially those of the peripheral nervous system, are described in the larva of Molgula citrina. In the peripheral nervous system, antibodies raised against acetylated α–tubulins mark a pair of rostral nerves arising from 8 to 10 sensory cells in the trunk epithelium, and a pair of tail nerves. In the sensory vesicle of the trunk, a pair of antennal cells is associated with the statocyte, and a tuft of ca. 150 cilia is labelled inside the hypophysial duct. A dorsal bundle of fibres forms a plexus over the surface of the sensory vesicle which extends caudally over the visceral ganglion. The latter contains somala that were back‐filled by Co2+–lysine through the cut tip of the tail. Antibodies directed against the transmitter candidates: peptides substance P, FMRFamide, somatostatin, neuropeptide Y, CGRP, VIP, and the amines: 5‐HT, dopamine, noradrenaline and GABA, all failed to demonstrate immunoreactivity anywhere in the nervous system. The trunk epithelium is ciliated uniformly but lacks papillae; this is remarkable given the presence of rostral nerves. The latter are presumed to be sensory, and can be compared with those in larvaceans and the larva of amphioxus. Sensory cells in the tail nerve, if present, lack cilia. The tail nerves are lateral in this species and presumed to be motor. © 1997 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd
Ultrastructure of the Cuticle of Loricifera and Demonstration of Chitin using Gold‐Labelled Wheat Germ Agglutinin
Authors: Neuhaus Birger , Kristensen Reinhardt Møbjerg , Peters Werner
Published: April 2010

The pharyngeal and lorical cuticles of adult and larval Loricifera were investigated by transmission electron microscopy. LR White sections of larval and adult Loricifera were labelled with the lectin wheat germ agglutinin (WGA) conjugated to colloidal gold. The pharyngeal cuticle of Nanaloricus mysticusexhibits a multilaminate epicuticle and an amorphous basal layer with osmiophilic fibres. The lorical cuticle consists of an osmiophilic or trilaminate epicuticle, one to three amorphous layer(s), and a basal fibrous layer which is strongly labelled by the lectin‐gold conjugate. Chitinase treatment or competitive inhibition with N‐, N′‐, N″‐triacetylchitotriose exclude labelling almost completely, whereas competitive inhibition with N‐acetyl‐D‐glucosamine does not affect labelling intensity. The binding of WGA in connection with competition experiments indicates the presence of chitin in the fibrous layer. In most areas of a section, three amorphous layers extend below the epicuticle of the Nanaloricidae. Only in favourably orientated sections can all three “amorphous” layers be seen to be formed by stacks of lamellae. Modified articulation sites with bundles of osmiophilic longitudinal fibres and an osmiophilic plate (Nanaloricidae only) occur in adult Loricifera, but not in the larval stages. The ultrastructure of the lorical cuticle of the Loricifera resembles that of other Nemathelminthes (= Aschelminthes). The morphology of the articulation sites and the number of lorical plates seem to differ between the Loricifera and Priapulida. Therefore, it is currently not possible to conclude whether the lorica of the Loricifera and Priapulida are homologous structures. © 1997 The Royal Swedish Academy of Sciences. Published by Elsevier Science Ltd.
Spermiogenesis in Paratomella rubra(Platyhelminthes, Acoela): Ultrastructural, Immunocytochemical, Cytochemical Studies and Phylogenetic Implications
Authors: Raikova Olga I. , Falleni Alessandra , Justine Jean‐Lou
Published: April 2010

Spermiogenesis and sperm structure of the primitive acoel Paratomella rubra from the Ligurian Sea, Italy, were investigated by several methods. During spermiogenesis, after flagellar incorporation by formation of two longitudinal lateral grooves, spermatid elongation is characterized in Paratomellaby the presence of four membranes encircling each axoneme plus two membranes encircling both the axonemes and the nucleus. These structures were interpreted as being three cytoplasmic canals situated one inside the other. The filiform spermatozoon has two incorporated axonemes of 9+2 type, a nucleus almost as long as the sperm cell itself, a single elongate mitochondrion, and two types of membrane‐bound granules, respectively, small and gastrula‐shaped, and large. Organelles are highly ordered, the sperm is bilaterally symmetrical with a single long mitochondrion on the ventral side and a regular row of large granules, for some length embedded in the nucleus, on the dorsal side. Immunocytochemical studies and the use of fluorescent nuclear dyes reveal the spatial relationships of the axonemes with the nucleus. The granules were shown by Thiéry, PTA and enzyme digestion tests to contain glycoproteins and/or polysaccharides and very little protein. Glycogen particles were detected in the cytoplasm. Cells containing coiled spermatozoa undergoing resorption were found in the parenchyma. New apomorphies of the taxon Paratomellabased on sperm structure are proposed: a very long nucleus, a highly bilaterally symmetrical pattern of organelles, a single long mitochondrion. These characters are not found in other Acoela, and particularly in Hesiolicium, sometimes considered closely related to Paratomella. © 1997 Published by Elsevier Science Ltd on behalf of The Royal Swedish Academy of Sciences.
Ultrastructure of Nuchal Organs in Polychaetes (Annelida) — New Results and Review
Authors: Purschke Günter
Published: April 2010

Nuchal organs are epidermal sensory structures present in most polychaetes. They are situated at the posterior edge of the prostomium and may extend posteriorly onto the peristomium. Although there is considerable external variation, they all consist of ciliated supporting cells, bipolar primary sensory cells and retractor muscles. They are innervated directly from the brain by paired nerves. The sensory cells are usually monociliated; their sensory processes lie in subcuticular spaces, the olfactory chambers. Structural variability is to be observed in the location of the sensory cells, the course of the nuchal nerve, position of nuchal ganglia as well as in cytological features of sensory and supporting cells. These differences provide useful characters for phylogenetic considerations to establish supraspecific taxa within the phylogenetic system of the Annelida. Special emphasis is laid on the problem of whether the nuchal organs represent an autapomorphy of the Polychaeta or the Annelida and thus whether the lack of nuchal organs in Clitellata is primary or secondary. As is discussed, the probability of a loss of the nuchal organs in Clitellata is higher, which favours the second hypothesis: that nuchal organs are part of the ground pattern of the Annelida and very likely are an autapomorphy of this group.
Spermiogenesis in Three Species of Whitefly (Homoptera, Aleyrodidae)
Authors: Bào Sönia N. , Kitajima Eillot W. , Callaini Giuliano , Lupetti Pietro , Dallai Romano
Published: April 2010

Aflagellate and immotile spermatozoa of three species of whitefly, Bemisia tabaci, Dialeroudes citriand Trialeroudes vaporariorum(Aleyrodidae), are described. In these three species, axoneme and mitochondria are present in the early spermatid, but degenerate in the later stages. The acrosome has arborescent appendages that almost completely surround the spermatozoan. In D. citrithe acrosomal projections are more elongated and branched than in T. vaporariorumand B. tabaci. Nuclear and cell elongation appear to occur in the absence of microtubules.
Studies on in vitro Extrusion and Ultrastructure of the Spermatophore in Haemaphysalis longicornis (Acari: Ixodidae)
Authors: Matsuo Tomohide , Mori Takayuki , Shiraishi Satoshi
Published: April 2010

Copulation in ticks is completed by the insertion of the spermatophore into the female genital aperture by a male. The endospermatophore, a cord‐like structure and contents are packed in the ectospermatophore of the completed spermatophore. The endospermatophore extrudes just after insertion of the tip of the spermatophore. Only the endospermatophore enters the female genital tract, and the ectospermatophore remains outside the female body. The extrusion is observed in vitro in Haemaphysalis longicornis at various concentrations of NaCl solution: the process is accelerated in less concentrated solutions. The cord‐like structure and the endospermatophore finally receive contents extruded from the ectospermatophore. The tip of the cord‐like structure connects to the surface of the endospermatophore, and together form a loop after extrusion. Ultrastructural observations confirmed that the ectospermatophore wall is composed of four layers, and the contents consist of male germ cells and three types of secretions from the male accessory genital glands. As in other ticks the male germ cells are elongated spermatids in spermatophores just after formation and extrusion. Adlerocysts described in other ticks are not found in the spermatophore of H. longicornis.