ON THE NEMATODES PARASITIC IN THE EARTHWORM 623 
Cori describes the larvae as occurring in almost all large speci- 
mens of Earthworms which were investigated in two or three 
localities in Central Europe (1). They are found only in the ventral 
vessel and throughout its length. When but a few parasites are 
present they lie one behind the other but if there be many they lie 
side by side. The young Nematodes are 2-4mm Iong, Omm{ broad 
about the middle of their body and slightly tapering at each end. 
The mouth is central and there are no lips or papillae. The cuticle is 
clearly ringed but the rings disappear close to each end, there are 
also faint longitudinal striations and a slight swelling along the 
lateral lines. Both cuticle and underlying structures are transparent 
and the alimentary canal is easily seen through them. 
The æœsophagus in followed by an æsophageal bulb and then by 
the intestine of a brown colour due to pigment corpuseles embedded 
in the epithelial cells forming the intestinal walls. The short rectum 
is free from this pigment. en 
The nerve ring lies at the posterior limit of the anterior third of 
the æsophagus and a little way behind it lies the excretory pore. 
Attempts to cultivate the Worms to a sexual condition in moist 
earth and in water were not successful. The Worms were however 
fortunately submitted to Professor von Linstow who recognized 
the resemblance they bore to certain larval stages which he had 
recognized in the stomachs of the various species of Turdus he 
had investigated. The larvae undoubtedly attain their second host 
when the latter eats the Earthworm hut how the Earthworm is 
infected has yet to he demontrated, probably by eating with its 
diet of earth sonie of the dejecta of the Bird. 
1) S. B. Deutsch. naturw.-medicin. Ver. für Bohmen, Lotos, 1898, p. 1. 
(1) : : » P 
