A new leech-infesting cercaria from Duddingston Loch, Edinburgh

Abstract

Valvata piscinalis, a common snail in the Duddingston Loch, Edinburgh, was found infected with a new furcocercous cercaria. Of 758 snails examined, 19 were found infected. This cercaria, which is named Cercaria valvatae n.sp., develops in long tubular sporocysts forming a tangled mass in the hepatopancreas of the snail. With the proliferation of the germ balls the tubular sporocyst becomes constricted into sausage-shaped swellings containing developing cercariae. The abbreviated specific diagnosis of Cercaria valvatae n.sp. (Fig. 1) is as follows.