The fine structure of the olfactory mucosa and nerve in the teleost Carassius carassius L.

Summary Morphological studies on teleost olfactory mucosa confirm the findings of previous authors regarding the general arrangement of conventional cell types, viz. receptor, sustentacular, mucous and basal, but teleosts show certain distinct differences. The receptor cells have the general mammalian bipolar shape but their peripheral dendrite does not project beyond the epithelial surface. In addition to numerous typical cilia, an exceptional ciliary formation was observed in which the filaments, instead of forming individual cilia, are grouped together in clusters and are enveloped in a single limiting membrane.At the junction between the finger-like process and the mucosal fold myelinated nerve fibres are observed within the subepithelial stroma.Within the postero-medial zone of the mucosa is a conspicuous well-differentiated new cell type. A thick rim of electron-dense cytoplasm, bounded by an outer trilaminar membrane, encloses prominent foliate (leaf-like) organelles, a basal nucleus, numerous mitochondria and vacuolar spaces. These foliaceous cells communicate with the external environment through a small stoma, their close association with epithelial components suggesting a possible secretory or absorptive function. Their intricate morphology, however, suggests that they may be receptors, but their role and neural connections still require definition.Supported by Grant 5 RO 5 TWOO 154-02 from the National Institutes of Health, United States Public Health Service.The authors are indebted to Dr. A. S. Wilson for his helpful criticism and gratefully acknowledge the photographic technical assistance of Mr. J. Simmons and Mr. S. Frank.     

Endocytosis in the ureteric duct epithelium of the hagfish (Myxine glutinosa L.)

Summary Solutions containing ferritin or thorotrast particles were microperfused through the ureteric duct of the hagfish. The markers were taken up by the epithelial cells by way of endocytosis and were transported in bulk in apical vesicles. Newly formed apical vesicles containing marker showed bristle coating on the cytoplasmic side of their limiting membrane. This coating appeared to be lost during the movement of vesicles deeper into the cytoplasm.The findings indicate that the epithelial cells in the ureteric duct have capablity for extensive bulk uptake of macromolecules from the luminal fluid. The mechanisms involved in absorption appear to be similar to those in proximal convoluted tubules of mammals.The apical dense tubules observed with some fixation techniques appear to represent collapsed endocytotic vesicles.The authors are indebted to Finn Walwig, Cand. real., Marine Biology Station, University of Oslo, Dröbak, Norway for kindly supplying the hagfishes used in this study. The technical assistance of Miss Signe Fjeldsenden and Miss Britt-Marie Pettersson is gratefully acknowledged.This work has been supported by grants from the Karolinska Institutet Medical School, Stockholm, Sweden (Therese och Johan Anderssons Minne).     

Ultrastructural observations on the body wall of the leech, Batracobdella picta

A series of closely spaced annulations surround the surface of the body of Batracobdella picta. The epidermis is covered by a thin cuticle which is composed of several layers of orthogonally arranged, fibrous bundles. Numerous fine projections carpet the surface of the cuticle and appear to be derived from microvillar processes which extend through the cuticle from subjacent epithelial cells. Septate junctions occur between adjacent epithelial cells, and hemidesmosomes with associated tonofilaments appear to anchor the epithelium to the overlying cuticle and to the basal connective tissue. The epithelial cells contain abundant organelles including granular endoplasmic reticulum, mitochondria and Golgi complexes. The cytology of the body wall of B. picta is compared with that of other annelids.     

Scanning and transmission electron microscopy of the tegument of Paranaella luquei Kohn, Baptista-Farias & Cohen, 2000 (Microcotylidae, Monogenea), parasite of a Brazilian catfish, Hypostomus regani

The surface topography and ultrastructure of the tegument of Paranaella luquei Kohn, Baptista-Farias & Cohen, 2000, a microcotylid monogenean parasite from the gills of Hypostomus regani (Ihering, 1905) (Loricariidae) was studied by scanning (SEM) and transmission electron microscopy (TEM). By SEM, it was observed that the tegument presents transversal ridges, forming folds in the ventral and dorsal surfaces and microvillous-like tegumental projections in the anterior and median regions of body. These projections were also observed by TEM. The tegument is made up of a syncytium delimited by apical and basal plasma membranes, containing inclusion bodies and mitochondria, connected to the nucleated region by means of cytoplasmatic processes. The tegumental cells present a well developed nucleus and cytoplasm containing inclusion bodies, similar to those found on the external layer, mitochondria, rough endoplasmatic reticulum and free ribossomes.     

The fine structure of the eye of the mollusc Pecten maximus

Summary The retina of Pecten maximus is divided into two light sensitive layers forming the distal and proximal retinae. The cells from these layers have different electrophysiological responses, the distal cells giving primary off responses, and the proximal cells giving on responses. The receptor surfaces of the distal retinal cells are formed from lamellae produced by the outer membranes of flattened cilia. These cilia have a basal body, basal foot, no root system and a 9 + 0 internal filament content. Each cell gives rise to an axon from its distal side, and this process goes up to the basement membrane, which is present below the cellular lens, passes along beneath it, and joins the distal optic nerve. The receptor part of the proximal retinal cells is formed from a vast array of microvilli. Each of these cells also bears one or two cilia with a probable 9 + 0 internal filament complement and no roots. The proximal cells give rise to axons, forming the proximal optic nerve. Below the proximal retina is a reflecting layer, the argentea, and below this is a pigment cell layer.We would like to acknowledge the advice and encouragement of Professor A. F. Huxley, Professor J. Z. Young and Dr. E. G. Gray. — We would like to thank Mrs. J. I. Astafiev for drawing Fig. 1, Mr. S. Waterman for photographic help and Miss C. Martin for clerical assistance.     

The fine structure of photoreceptors in a marine flatworm

Summary The ocelli or eyes of the marine polyclad turbellarian Notoplana acticola are clustered on the paired dorsal nuchal tentacles and in two longitudinal bands lateral to the cerebral ganglion. The ocelli, studied by electron microscopy, were characterized as rhabdomeric and non-ciliary in origin. There are 60 to 80 ocelli per animal each enclosed in a fibrous capsule to which muscle fibers may attach. An ocellus consists of a pigmented eyecup into which 30 to 50 photoreceptor cells send dendritic processes through interruptions in or among pigment cell projections across the eyecup opening. The dendritic processes terminate in numerous long intertwined microvilli which fill the eyecup. The nucleated cell body of each photoreceptor cell lies outside the eyecup and projects an axonal process to the cerebral mass. Within the dendritic processes are observed mitochondria, ribosomes, neurotubules, multivesicular bodies, vesicles and vacuoles. The cell body contains smaller mitochondria, endoplasmic reticulum, ribosomes, vesicles and prominent Golgi complexes.After dark adaptation, there are some structural alterations in terms of swelling of microvilli, increased numbers of vacuoles associated with the microvilli and dendritic processes, and changes in the pigment cell projections.This work was supported by Grant No. GM 10292 from the U.S. Public Health Service to Professor Richard M. Eakin, Department of Zoology at the University of California, Berkeley, U.S.A., where this investigation was conducted during the author's sabbatical leave of absence from the University of Illinois, and by Grant No. 1 SO 1 FR 5369 from the U.S. Public Health Service to the University of Illinois at the Medical Center.I express appreciation to Professor Eakin for interesting discussions and generous hospitality to me as a guest in his laboratory, and to the John Simon Guggenheim Memorial Foundation for the Fellowship which I held during 1964–65. I thank Dr. John P. Marbarger, Director of the Aeromedical Laboratory for the electron microscope facilities used at the University of Illinois.     

THE FINE STRUCTURE OF EPENDYMA IN THE BRAIN OF THE RAT

The ciliated ependyma of the rat brain consists of a sheet of epithelial cells, the luminal surface of which is reflected over ciliary shafts and numerous evaginations of irregular dimensions. The relatively straight lateral portions of the plasmalemma of contiguous cells are fused at discrete sites to form five-layered junctions or zonulae occludentes which obliterate the intercellular space. These fusions occur usually at some distance below the free surface either independently or in continuity with a second intercellular junction, the zonula adhaerens. The luminal junction is usually formed by a zonula adhaerens or, occasionally, by a zonula occludens. The finely granular and filamentous cytoplasm contains supranuclear dense bodies, some of which are probably lysosomes and dense whorls of perinuclear filaments which send fascicles toward the lateral plasmalemma. The apical regions of the cytoplasm contain the basal body complexes of neighboring cilia. These complexes include a striated basal foot and short, non-striated rootlets emanating from the wall of each basal body. The rootlets end in a zone of granules about the proximal region of the basal body, adjacent to which may lie a striated mass of variable shape. All components of the basal body complex of adjacent cilia are independent of each other.     

Development of the ciliary complex and microtubules in the cells of rat subcommissural organ

Summary The fine structure of the rat subcommissural organs from the late stages of gestation through the postnatal to the adult stages was studied with the electron microscope. Emphasis in this report is placed on the development of the cilium with its affiliated structures. With the progress of cytodifferentiation centrioles originally located in the Golgi region migrate to the cell apex, where each then serves as a basal body to form a cilium which has a 9+2 organization of substructures. Thus, each of the mature subcommissural cells is provided with two cilia of motile type. Satellites first appear on one side of the basal body at about 17 fetal days, rapidly increase in number with age, and finally surround the basal body, forming an elaborate latticework. In the perinatal period microtubules progressively increase in number in the distal cytoplasm, which concurrently elongates and forms a prominent projection in the brain ventricle. Closely associated with the microtubules are large clusters of dense granular masses with an undefined border, which bear a close resemblance to the dense masses appearing in the differentiating cells of respiratory epithelium and having been generally assumed to be the precursor substance for centriole replication. However, the mature subcommissural cells contain no centrioles other than the preexisting pair, each of which has organized a cilium. The dense masses in the subcommissural cells are presumed to be involved in the formation of the cytoplasmic microtubules instead of new centrioles.Work supported by the National Science Council, the Republic of China, and by the China Medical Board of New York, Inc. A preliminary report was presented at the 6th International Congress for Electron Microscopy, Kyoto, 1966 (Lin, H.-S., andI-1. Chen: Satellites of the ciliary basal body and microtubules in the cells of the rat subcommissural organ. In: Electron Microscopy (R. Ueda, ed.) Vol. II, 461–462. Tokyo: Maruzen Co., Ltd. 1966).     

Kanamycin-induced changes in cochlear hair cells of the guinea pig

Summary Electron-microscopical studies on the organ of Corti in kanamycin-intoxicated guinea pigs showed that progressive changes occurred in the cochlear hair cells. The changes appeared first in the basal turn of the organ of Corti, and affected primarily the outer hair-cells. During the later stages of intoxication, degeneration spread from the basal turn upwards, in the direction of the apex of the cochlea and, finally, affected all the external hair-cells.The early changes caused clumping of the chromatin in the nucleus, swelling of the nuclear membrane, damage in the mitochondria, with vesiculation of the mitochondrial cristae, and the formation of lamellated structures. The lysosomes were converted into dense bodies exhibiting various degeneration patterns. The ribosomes disappeared at an early stage from the cytoplasm.Even in cells where severe changes had occurred the hairs and cuticle seemed to be intact.During the final stages the plasma membrane, as well as the hairs and cuticle, was destroyed, and only remnants of these structures remained.Even after the disappearance of the sensory cells and the afferent nerve endings, some efferent nerve endings were still present in the organ of Corti.The action of kanamycin seems to differ slightly from that of streptomycin, since the changes caused by kanamycin in the plasma membrane are a fairly late effect, whereas the earliest changes occur apparently in the RNA protein-synthesis system and in the mitochondria of the external hair-cells.

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Zusammenfassung Elektronenmikroskopische Untersuchungen am Cortischen Organ von Meerschweinchen mit Kanamycinintoxikation ergaben eine fortschreitende Schädigung der cochlearen Haarzellen. Die Veränderungen begannen in der basalen Schneckenwindung und betrafen vorwiegend die äußeren Haarzellen. In späteren Intoxikationsstadien breitete sich die Degeneration von der Basalwindung nach aufwärts bis in die Schneckenspitze aus und wurde schließlich an allen äußeren Haarzellen gesehen.Die früheren Veränderungen manifestierten sich am Kern mit Chromatinverklumpung, Schwellen der Kernmembran, Schädigung der Mitochondrion mit vesikulären Cristae mitochondriales und Bildung von Lamellenstrukturen. Die Lysosomen waren in dichte Körper verwandelt und wiesen verschiedene Degenerationsmuster auf. Die Ribosomen verschwanden früh aus dem Cytoplasma. Sogar in schwer geschädigten Zellen erschienen Haare und Cuticula intakt.In den Endstadien waren Plasmamembran, Haare und Cuticula bis auf Reste zerstört. Einige efferente Nervenendigungen waren selbst nach dem Verschwinden der Haarzellen und der afferenten Endigungen noch anzutreffen.Die Wirkung von Kanamycin ist offenbar etwas anders als die von Streptomycin, da die Veränderungen an der Plasmamembran ziemlich spät auftreten, während sich die frühesten Schäden im System der RNA-Proteinsynthese und in den Mitochondrien der äußeren Haarzellen zu manifestieren scheinen.

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This investigation was supported by Grant No. NB 3956-03 from the US Public Health Service, the Swedish Medical Research Council, and Stiftelsen Therese and Johan Anderssons Minne. The skillful technical assistance of Miss Cathrine Lindholm, Miss Ann-Marie Lundberg, Miss Sonja Löfvenius, and Miss Gunilla Wiman is gratefully acknowledged. The kanamycin was kindly supplied by AB H. Lundbeck & Co.     

Fine structure of cilia in rat cerebral cortex

Summary Cilia have been demonstrated on granular neurons and astroglial cells in the fascia dentata, a part of the hippocampal region, in the rat. Every granular cell seems to possess one cilium, which shows an 8+1 pattern in the greater part of its length. This 8+1 pattern is shown to result from the displacement of one peripheral doublet of a 9+0 cilium into the middle of the cilium. The neuronal cilia have a two-centriole basal organization, and fine rootlets radiate from the basal body proper into the cytoplasm. The possible function and significance of these cilia are discussed on the basis of earlier literature.This study was supported in part by Grant NB 02215 of The National Institute of Neurological Diseases and Blindness, U.S. Public Health Service, in part by The Norwegian Research Council for Science and the Humanities. This aid is gratefully acknowledged. I am greatly indebted to Dr. Th. Blackstad for encouragement and advice during this study, to Mrs. J. L. Vaaland, Mr. B. V. Johansen and Mr. E. Risnes for technical assistance, and to Dr. B. Afzelius for valuable discussions.     

Scanning and Transmission Electron Microscopic Observations on Surface Structures of Three Turbellarian Species

The body surface of Microstomum lineare, Bothriomolus balticus and Archilopsis unipunctata was examined in scanning electron microscope. The threedimensional appearance of adhesive duo-gland organs, receptor cilia, globular bodies and pistil-like projections is described. The adhesive duo-gland papillae of Bothriomolus and Archilopsis appear as bouquetlike structures on either side of the tail as well as on the cilia covered body. In Microstomum the papillae occur as single projections among the ciliary body für. Supplementary TEM investigation revealed crystalline bodies in the cytoplasm of viscid gland cells.     

On the glycocalyx,the external coat of the plasma membrane,of some secretory cells

Summary The free surface of epithelial cells of secretory organs (human placenta, lactating mammary gland of the rat, choroid plexus of man and rat) and of the accessory organs of the genital tract of the male rat is characterized by a plasmalemmal differentiation named glycocalyx or surface mucous coat. This structure is built up by filamentous or globular substructures.Two main ultrastructural types of the glyeocalyx were observed: 1) The filamentous type such as in the rat epididymis, which resembles the cat intestinal glyeocalyx (Ito, 1965) and that one of human transitional epithelium (Monis and Zambrano, 1968), and 2) The globular type, as observed in the lumen of the lactating mammary gland of the rat.Sialic acid was demonstrated histochemically in the luminal glyeocalyx of all organs studied. In addition, the glyeocalyx of acinar cells of the lactating mammary gland contains sulfate and phosphate groups which were identified by histochemical technics, using enzymatic digestion procedures, suggesting the chemical heterogeneity of this glyeocalyx.Present investigations follow the working hypothesis that the complex carbohydrates of glycocalyces become part of the product of activity of secreting cells.We thank Mr. Luis Iwakawa, Miss Silvia Falcón, Miss Elsa M. Orgnero for technical help, Miss Graciela Aliaga for secretarial assistance. Photography by Mr. H. Magnani. Dr. Hugo F. Carrer cooperated in the initial stages of this investigation.The authors acknowledge the use of the electron microscope of the Department of Pathology, Córdoba University Medical School, for which they thank Prof. E. Mosquera and Dr. E. Hliba. Dr. Hliba photographed picture number 4.     

Early postmortem changes in the Organ of Corti (guinea pig)

Summary Early post mortem changes in the Organ of Corti are described. 15 minutes after death, when kept at room temperature, 20° C (63° F), an oedematous swelling is observed within the cytoplasm of hair cells and nerve endings, the latter being more severe affected. After 30 minutes post mortem the mitochondria of the hair cells have also become significantly swollen. Three hours post mortem the general character of the hair cells is still recognizable, but most of the nerve endings have been completely destroyed. Acknowledgement. We wish to express our appreciation of the skilful technical assistance of Mrs. B. Flock, Miss A.-M. Lundberg, Miss Sonja Löfvenius, Mr. G. Bornholm and Mr. Rune Ragnefjell.This work was supported by grants from the Swedish Medical Research Council, the National Institute of Health grant (no NB 03956-02), the Therese and Johan Anderssons minne, the Gustav and Tyra Svenssons fund and the King Gustav V Research Fund.     

The integument of the Queensland fruit fly,Dacus tryoni (Frogg.)

Summary Testes of the Japanese freshwater turtle Clemmys japonica Temmnick et Schlegel were fixed in 3% potassium permanganate buffered to pH 7.2 with Veronal-acetate buffer, and thin sections of the tissue, embedded in epoxy Epon resin, were studied under the electron or light microscope.At the early stage of differentiation of the spermatid, the cytoplasm contains a few mitochondria provided with cristae which are oriented transversely or longitudinally. As the differentiation of spermatids proceeds, the mitochondrion has been modified into a cupshaped body with a wall consisting of several concentric layers. Such body has been referred to the mitochondrial lamellar body. The formation of such a body is mainly attributed to the mitochondrial cristae, and subsequently to the membrane system of the endoplasmic reticulum. In a more advanced stage of differentiation, the mitochondrial lamellar bodies appear wrapped around a bundle of tail filaments, and seem to present a very wide surface available for the localization of organized enzyme systems to facilitate the motion of spermatozoa.Prior to the formation of the mitochondrial lamellar bodies, the Golgi apparatus has been reorganized into a peculiar body with a floral appearance, consisting of numerous tubular elements, and revealing to be positive in PAS-reaction. The body has been designated as the tubular body which has never been demonstrated in any spermatogenic cells through animal kingdom.One to three tubules oval in cross section, approximately 430 × 700 Å in diameter, have been found in the nucleoplasm along the longitudinal axis of a greatly elongated, cone-shaped nucleus of the spermatid. The tubules open on the apex surface of the nucleus, but they are not encountered in the acrosome. A possible physiological significance of the tubules has been discussed in view of the function of the acrosomal tubules in the decapod and other species spermatozoa as well as on the basis of the metabolism of nucleus.This study was supported by Grant GM-8327 from the United States Public Health Service.We wish to express our gratitude to Dr. B. A. Afzelius, Wenner-Gren Institute, University of Stockholm, for his valuable suggestion to the present work.     

Ultrastructure of the full-term shark yolk sac placenta. II. The smooth, proximal segment

The smooth, proximal portion of the yolk sac placenta of the sandbar shark, Carcharhinus plumbeus is comprised of: (1) An outermost epithelial ectoderm; (2) an intervening collagenous stroma; and (3) an inner mesothelium. The surface epithelium may be one to three cell layers thick. The surface epithelium comprises two cell types. A cuboidal cell that has a dome-like apical surface covered with microvilli and an ovoid nucleus predominate. These cells contain lipid inclusions, many cytoplasmic filaments, and are joined by desmosomes. The second cell type has a convoluted nucleus and a flattened cell apex with microvilli, cilia, and paddle cilia. Golgi complexes and elements of the endoplasmic reticulum are relatively uncommon in the cytoplasm of both cell types. Microplicae also occur on the surface of some cells. The smooth, proximal portion of the placenta is sparsely vascularized. The innermost cellular elements of the surface epithelium rest on a prominent basal lamina. A collagenous zone separates the epithelial basal lamina from the basal lamina of the mesothelium. The mesothelial cells are squamous with a fusiform nucleus, many pinocytotic pits and vesicles, and a large number of cytoplasmic filaments. The endoplasmic reticulum, except for occasional patches of the rough type, and the Golgi complex are poorly developed. Ultrastructural tracer studies show that this portion of the placenta does not absorb horseradish peroxidase (HRP) and trypan blue.     

Cilia-lacking respiratory cells in ciliary aplasia

This report describes the ultrastructural alterations observed in the nasal and bronchial mucosa of an 11-yr-old male suffering from immotile cilia syndrome (ICS). The morphological features observed in this patient are consistent with a ciliary aplasia. In fact, ciliated cells appeared to be replaced by columnar cells lacking cilia and basal bodies, and bearing on their surface cilium-like projections without any internal axonemal structure. In spite of the absence of basal bodies, centrioles, and kinocilia, these cells unexpectedly showed mature striated roots and centriolar precursor material scattered throughout the apical cytoplasm. These data suggest that control over basal body assembly is distinct from control over striated root formation. The presence of the above-reported structures in cells otherwise presenting many morphological features of normal ciliated cells is discussed on the basis of current knowledge of respiratory cilia biogenesis.     

Orchid embryology: Pollen tetrads of Epidendrum scutella in the anther and on the stigma

Summary The pollinium of Epidendrum scutella, both in the anther and on the stigma, was examined with the electron microscope. The sporoderm of the outer tetrads has a sexine and an intine while that of the inner tetrads lacks a sexine, and an intine is formed only after the pollinium is on the stigma. A fibrous wall layer apparently holds the tetrads together. The cytoplasm is filled with plastids, mitochondria, polysomes, vacuoles and vesicles of various sizes, and endoplasmic reticulum (ER) with narrow cisternae. The vegetative nucleus is oval in form and contains a large nucleolus. The generative nucleus is deeply lobed and contains a well-developed nucleolus. The generative cytoplasm lacks both plastids and mitochondria and has little ER. Dictyosomes are present as well as assorted vesicles. A pocket is present between the plasma membrane of the generative cell and the wall; it contains assorted membranes and ribosome-like particles. After the pollen is on the stigma the wall surrounding the generative cell begins to disappear and gaps develop in it.This investigation was carried out during the tenure of a research fellowship from the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.Research supported by grants from National Science Foundation (GB-3460) and the Miller Institute for Basis Science at the University of California, Berkeley. The authors would like to thank Miss Mary Ashton for her assistance in the research.     

Starvation effects on the ultrastructure of amoeba mitochondria

Summary Mitochondria in non-starved giant amoebae, Pelomyxa carolinensis, contain tubules lying at random in the matrix. Many mitochondria in starved amoebae have enlarged tubules aligned in a zigzag pattern. Tubules within the zigzag region are separated by very little matrix material. Some of these altered mitochondria are found in 70% of amoebae starved for only 24 hours, and in nearly all P. carolinensis starved for 8 days or longer. The percentage of such altered mitochondria increases from zero in most well-fed amoebae, to about 60% after two weeks of continuous starvation. Most P. carolinensis starved at 25° C survive less than three weeks. Microfilament bundles are observed in the matrix of some mitochondria in amoebae starved for more than two days.Work supported by the U. S. Atomic Energy Commission.The authors acknowledge the assistance of Miss Doris Jean Buer and Miss Patricia Ann Sustarsic.     

II. Ultrastructure of the type B sense organ of the specific lateral line system of Gymnarchus niloticus

Summary The type B cutaneous receptor represents one of the three kinds of specific organs of the lateral line system of Gymnarchus niloticus (Szabo and Barets, 1963). Electron microscopic observations reveal that the elementary unit (Fig. 18) of the type B organ consists of a well organized assembly of different epithelial elements grouped around each sensory cell. Several such units compose a type B organ innervated by a single myelinated nerve fiber.The cytoplasm of the sensory cell is characterised by a deep invagination lined by long and densely packed microvilli covered by a jelly-like substance. This jelly substance of allongated stylet form is situated in an intraepidermal cavity, overlaid by vacuolised epithelial cells oriented perpendicularly toward the external epidermal surface.Certain morphological characteristics of the organ B allows the conclusion that this organ is one of the possible electroreceptors of the Gymnarchus niloticus.This work was supported by grant No. 659535 of the Direction de Recherches et Moyens d'Essais (D.R.M.E.) to Dr. Szabo.This work was carried out on the electronmicroscope of the Service de Microscopie Electronique du Laboratoire de Médecine Experimentale (RCA) et du Laboratoire d'Histologie Normale et Pathologique du Système Nerveux (Siemens).With the technical assistance of Miss L. Seguin and Mr. C. Pennarun.     

A multiciliate ‘starcell’ in the parenchyma of the larva of Austramphilina elongata (Amphilinidea)

Rohde K. and Garlick P. R. 1985. A multicilite ‘starcell’ in the parenchyma of the larva of Austramphilina elongata (Amphilinidea). International Journal for Parasitology15: 403–407. The ultrastructure of a new cell type is described. It is located at the posterior end of the penetration glands of larval Austramphilina. Large numbers of cilia of the cell protrude in all directions into adjacent fluidfilled spaces. The cell is rich in mitochondria and has a cavity which is separated from the surrounding tissue spaces by a sheath of cytoplasm and by ribs of cytoplasm with a membrane between them. Leptotriches project from the cell body into the cavity. Possible functions of the cell are discussed.