STUDIES ON THE TURBELLARIA. 457 
the brain to join the corresponding vessel from the opposite 
side, while the other runs forwards to join the anterior pro- 
longation of the ventral vessel. 
Posteriorly both vessels usually become wider. In some 
specimens they united behind some distance from the middle 
line, and there was no evidence of any approximation of the 
right and left vessels, so that there would appear to be two 
separate excretory apertures at or near the posterior ex- 
tremity. 
Both of these longitudinal vessels were sometimes observed 
to contract peristaltically, sometimes with an approach to 
regularity. 
A small number of ciliary flames were observed in very 
close relation to the main vessels—so close in fact that they 
moved with the movements of the vessel in such a way that 
they actually seemed to lie in the interior of the cells, forming 
its wall, or to be contained in extremely short branches. 
In view of the meagreness of the above statement, it would 
scarcely be profitable to institute a systematic comparison 
between the excretory system of Anomaloccelus and those 
of described genera of Rhabdoceeles. Apparently, so far as 
the arrangement of the main trunks and their mode of open- 
ing is concerned, the nearest alliance is with the V orticida. 
The statements of O. Schmidt (25), Hallez (18, p. 21), and 
von Graff lead to the conclusion that, whereas in Vortex the 
main vessels open in the neighbourhood of the pharynx, if 
not actually into the pharyngeal sac, in Derostoma they 
open on the exterior by two apertures situated towards the 
posterior extremity. More recently Fuhrmann (7) has stated 
that in this respect Vortex and Derostoma are alike—the 
apertures in both genera being situated far back. 
Reproductive Apparatus.—The testis is diffuse, its 
lobes extending throughout the part of the body situated 
behind the pharynx. Definite ducts are not developed, but 
by some means the sperms filter through channels in the 
parenchyma to the vesicula seminalis, which is situated in the 
anterior part of the space enclosed by the penis sheath, 
VoL. 49, PART 3. —NEW SERIES. 33 
