281 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



bilinearis), and I think it probable that the distome 

 described here is the above species. 



Measurements made from a specimen killed in fresh 

 water and preserved in formalin are : — 



Length : 2 to 2'5 mm. 



Breadth : 0'25 to 0*5 mm. 



Diameter of oral sucker: 0*23 mm. 



Diameter of ventral sucker : 0'42 mm. 



Diameters of ova : 0*08 x O04 mm. 

 Fig. 15 represents one of these worms seen rather 

 from the side, but slightly twisted. The skin is smooth 

 and without armature; the body sub-cylindrical, and in 

 death with a very noticeable bend towards the anterior 

 extremity. The ventral sucker is very prominent, and is 

 situated on a kind of protuberance. It is nearly twice the 

 diameter of the oral sucker. The pharynx is large, and 

 there is a short oesophagus — the intestinal forks run 

 straight back to near the posterior extremity. The ovary 

 is situated about halfway between the extremities, is 

 globular in shape and rather small. Immediately in front 

 of it is the uterus, which in most specimens formed a 

 compact mass consisting of, apparently, few convolutions 

 and containing a comparatively small number of eggs. 

 The vitellaria are very conspicuous structures, and in 

 many specimens filled the body, almost preventing a 

 proper view of the other genital organs. There are 

 usually four bands of rounded, irregularly-shaped gland ; 

 in the figure these bands are seen from the edges, but 

 when the worm is rotated through 90° they appear to be 

 much more voluminous, the bands then being seen from 

 the flat sides. In many specimens the vitelline ducts are 

 very conspicuous, they run through the middle of the 

 band-like masses of vitellaria, and join to form a trans- 

 verse duct which runs across the body. The ovary is 



