193 
NOTE ON THE ANATOMY OF 
CYST1D1 COLA FARIONIS. 
By R. T. LEIPER, M.B., F.Z.S. 
Helminthologist to the London School of Tropical Medicine. 
The nematode worms discovered by Mr Shipley in the swim-bladder 
of Trout belong to the species Cystidicola farionis, first described by 
Fischer, and considered by him to represent a new and distinct type in 
nematode structure for which he proposed the generic name Cystidicola. 
Later writers refused to accept the new genus and included it in various 
other groups (see Synonymy, p. 190). In accordance with an old nomen- 
clatural practice the proposed generic name was adopted as the specific 
name in place of that originally given, thus Cystidicola farionis became, 
for Rudolphi, Spiroptera cystidicola. From a detailed examination of 
the various characters of C. farionis I have come to the conclusion that 
Fischer was correct in creating a new genus for the new forms, and I 
therefore propose the reinstatement of the abandoned name Cystidicola. 
It is also in accordance with modern nomenclatural ruling that the original 
specific name farionis should be adopted in place of cystidicola. 
The anatomy of C. farionis. 
The body is very slender and translucent, it tapers gradually from 
the middle third to both ends of the body. In preserved specimens the 
male is coiled posteriorly in a spiral manner and measures about 14 mm. 
in length. The female remains perfectly straight, measuring 22—26 mm. 
x '3 mm. The cuticle is thin and without transverse striation. At the 
posterior end of the male it expands to form a narrow ala on either side 
supported by the genital papillae. In the female its uniformity is 
disturbed only by a tiny pair of papillae near the tip of the tail. 
The alimentary canal shows the usual differentiation into oesophagus, 
chyle intestine and rectum, the first-named structure presenting 
characters that associate Cystidicola with the other genera of the family 
Spiruridae. The mouth is a simple spherical orifice surmounted by two 
hook-like teeth that in shape recall the “ external tooth ” of Physaloptera 
species. It gives access to a deep cylindrical mouth capsule with thick 
