Faculty Opinions recommendation of Functional evolution of vertebrate sensory receptors.

It has been suggested that parasitism results in a reduction of sensory structures which concomitantly reflects a reduction in the complexity of the nervous system. The present study tests this hypothesis by examining the fine morphology and the distribution of sensory receptors for two species of aspidogastrid trematodes by transmission and scanning electron microscopy. The species chosen are an ectoparasite, Cotylaspis insignis and an endoparasite, Aspidogaster conchicola.Aspidogaster conchicola and Cotylaspis insignis were obtained from natural infections of clams, Anodonta corpulenta and Proptera purpurata. The specimens were fixed for transmission electron microscopy in phosphate buffered paraformaldehyde followed by osmic acid in the same buffer, dehydrated in an ascending series of ethanol solutions and embedded in Epon 812.

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Scanning electron microscopy of the integument of schistosoma rodhaini

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014230x ◽

1986 ◽

Vol 44 ◽

pp. 132-133

Author(s):

P. Evers ◽

C. Schutte ◽

C. D. Dettman

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Oral Sucker ◽

Adult Male ◽

Dorsal Surface ◽

Ventral Surface ◽

Sensory Receptors ◽

East African ◽

Dorsal Midline ◽

Scanning Electron

S.rodhaini (Brumpt 1931) is a parasite of East African rodents which may possibly hybridize with the human schistosome S. mansoni. The adult male at maturity measures approximately 3mm long and possesses both oral and ventral suckers and a marked gynaecophoric canal. The oral sucker is surrounded by a ring of sensory receptors with a large number of inwardly-pointing spines set into deep sockets occupying the bulk of the ventral surface of the sucker. Numbers of scattered sensory receptors are found on both dorsal and ventral surfaces of the head (Fig. 1) together with two conspicuous rows of receptors situated symmetrically on each side of the midline. One row extends along the dorsal surface of the head midway between the dorsal midline and the lateral margin.

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The distribution and density of ciliary tufts on the siphons of Anodonta cygnea (Mollusca: Bivalvia)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160145 ◽

1990 ◽

Vol 48 (3) ◽

pp. 518-519

Author(s):

Wen-lung Wu

Keyword(s):

Osmium Tetroxide ◽

Internal Surface ◽

Mechanical Stimuli ◽

Type Ii ◽

Sensory Receptors ◽

Anodonta Cygnea ◽

Type Iv ◽

Sem Study ◽

Inhalant Siphon ◽

Type V

The mantle of bivalves has come entirely to enclose the laterally compressed body and the mantle margin has assumed a variety of functions, one of the pricipal ones being sensory. Ciliary tufts, which are probably sensory, have been reported from the mantle and siphons of several bivalves1∽4. Certain regions of the mantle margin are likely to be more or less, sensitive to certain stimuli than others. The inhalant siphon is likely to be particularly sensitive to both chemical and mechanical stimuli, whereas the exhalant siphon will be less sensitive to both. The distribution and density of putative sensory receptors on the in-and ex-halant siphon is compared in this paper.The excised siphons were fixed in glutaraldehyde and osmium tetroxide, the whole procedure of SEM study is recorded in Wu's thesis.Type II cilia cover the tips of tentacles, 6.13um. Type IV and type V cilia are found on the surface of tentacles. Type IV cilia are occasionally present at the tips of tentacles, 8 um long. They are the commonest type on the surface of tentacles. Type VI cilia occor in the internal surface of the inhalant siphon, but are not found on the surface of tentacles, 6.7-10um long.

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