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Some Observations and Experiments on the Biology of Larval Trematodes

Published online by Cambridge University Press:  06 April 2009

Gwendolen Rees
Affiliation:
Department of Zoology, University College, Cardiff.

Extract

1. Experiments on the liberation of cercariae from their snail hosts have shown that under normal conditions C. limbifera (Seifert) and Cercaria “Z” n.sp. emerge during the day-time only, while in C. cambrensis I (Wright) the emergence takes place during the whole twenty-four hours, but considerably more so during the night-time.

Continual darkness causes a decrease in the numbers emerging, and a lowering of the temperature partially or completely checks the escape of the larvae.

In Cercaria “Z” there is a double maximum between 11 a.m. and 4 p.m. in the numbers liberated.

The invasion of L. truncatula by the larval stages of Fasciola hepatica leads to the disintegration of the host's tissues, the appearance of black pigment and the reduction of the liver cells to a thin layer of protoplasm containing the nuclei.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1931

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References

Agersborg, H. P. K. (1924). Studies on the effect of parasitism upon the tissues. I. With special reference to certain gastropod molluscs. Quart. J. Micr. Sci. 68, 361401.Google Scholar
Cort, W. W. (1922). A study of the escape of Cercariae from their snail hosts. J. Parasitol., Urbana, 8, 275281.CrossRefGoogle Scholar
Dubois, G. (1929). Les Cercaires de Ia région de Neuchâtel. Bull. Soc. neuchât. Sci. nat. 53.Google Scholar