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A comparative study of the glandular and excretory systems of the oncomiracidia of the monogenean skin parasites Entobdella hippoglossi, E. diadema and E. soleae

Published online by Cambridge University Press:  06 April 2009

Graham C. Kearn
Affiliation:
School of Biological Sciences, University of East Anglia, Norwich, NOR 88C, U.K.

Extract

A comparison of the oncomiracidia of the monogenean skin parasites Entobdella hippoglossi from the halibut (Hippoglossus hippoglossus), E. diadema from the sting ray (Dasyatis pastinaca) and E. soleae from the skin of the common sole (Solea solea) has revealed the presence of ‘body gland cells’, all of which have openings on the ventral or lateral surfaces of the larvae. In all three species there are two pairs of glands lying in the posterior region of the body proper with long ducts extending into the haptor and opening on its ventral surface. In addition to these two pairs of glands there are seven other pairs of body glands in E. hippoglossi, six pairs in E. diadema and two pairs in E. soleae. In E. soleae all the ‘body gland cells’ are poorly developed in the oncomiracidium and are more conspicuous in post-oncomiracidia. The fate of the ‘body gland cells’ during post-oncomiracidial development has been studied in E. soleae, and their possible functions are discussed. The glands in the head region (anterior median, posterior median and lateral head glands) are similar in all three species. Gland cells associated with the alimentary system are less easy to observe but differences between the three species appear to be small.

In the oncomiracidia of all three species the number of flame cells and their distribution are the same, but the oncomiracidia of E. hippoglossi and E. diadema have loops in the excretory ducts anterior to the bladder and the bladders of E. diadema contain refringent bodies.

The oncomiracidial eyes of E. hippoglossi and E. soleae have lenses but the lenses are greatly reduced in the oncomiracidia of E. diadema. In the three larvae there are small but characteristic differences in the shapes of the accessory sclerites.

The oncomiracidium of E. hippoglossi has not previously been described.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1974

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References

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