232 
THE TANGANYIKA PROBLEM. 
valvular fold which becomes doubled near the aperture of 
a bile duct, and then passes, as in TrocJius , into a small, but 
quite well developed, spiral caecum. Except for the presence 
of the anterior chamber, which appears to be absent in the 
genus TrocJius, Chytra possesses a stomachic apparatus 
F>g- 1 5- — The nervous system of Chytra kirkii dissected from above. (From a 
drawing by Miss Digby.) 
strictly comparable to that in the majority of the Rhipido- 
glossa, including Pleurotomaria itself. 
The intestine leaves the stomach on the left, and after a 
characteristic double twist, enlarges into the rectum. This 
enlarged rectum is filled with complex glandular folds, but 
narrows again before it opens at the anus, which has a 
distinctly modified rim. 
The heart has the typical Taenioglossate characters, and 
