138 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



The body Is nearly cylindrical, and is only flattened 

 dorso-ventrally at about the middle of the length. It is, 

 as a rule, nearly uniform in diameter only tapering gently 

 at either extremity. The skin possesses no spines or other 

 form of armature. 



Fig. 1. Allocreadium labracis (Duj.). Median longitudinal section 

 through mouth and pharynx. 



The mouth is subterminal, as is indicated in fig. 1, 

 which represents part of a median longitudinal section. 

 Immediately following the oral sucker, and connected to 

 it by a delicate tube is a strongly muscular, nearly 

 globular pharynx of the usual type. The lumen of the 

 pharynx is a longitudinal dorso-ventral slit, the inner 

 surfaces of which are hard and fibrous. The pharynx 

 passes immediately into a rather short oesophagus which, 

 almost at once, bifurcates to form the two intestinal rami. 

 The two branches of the intestine run roughly parallel to 

 each other to almost the posterior extremity of the body. 

 They have a nearly uniform diameter throughout. The 

 lumen is not a simple one throughout. Round the peri- 

 phery the wall is produced axially into the lumen as a 

 loose vacuolated tissue, the central vacuoles being larger 

 and continuous with each other, and this is the case as 

 far back as the middle of the body. From thence back- 

 wards the vacuolated tissue in the intestine becomes 



