282 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



caught in Barrow Channel were infested with the same 

 parasite, and in the same tissues. There is no doubt that 

 these trematodes are common parasites of gadoid fishes. 



PL IV., fig. 8, represents one of the encysted worms 

 from the brain of Phycis. The whole structure is about 

 0*8 mm. in longest diameter. It is loosely attached to the 

 dura mater, or other membrane, by a fold of the latter. 

 The cyst itself is very thick and tough, and is rather 

 opaque. Within it is the bent up body of the cercaria. 

 In the specimen figured little could be made out of the 

 internal anatomy, except the testes and the cirrus. 

 Others were, however, more advanced, and some had 

 emerged from the sac. In the small cod mentioned above 

 most of the parasites were free from the cysts, but were 

 still very small. In a haddock, which was well infested, 

 the worms were much larger — 1*5 to 2 mm., and it is one 

 of these which is represented in fig. 7. 



In these worms the reproductive organs are well 

 developed. The cirrus and its sac vary very greatly in 

 length; the testes are large and prominent objects. The 

 uterus is long and twisted, the germarium is small, and 

 lies closely opposed to another structure which I cannot 

 identify. The vitellaria are well developed, but it is 

 difficult or impossible to trace their ducts with any 

 certainty. The anterior sucker is ventral in position, is 

 large and nearly round; the pharynx is situated in the 

 anterior third of the body, and leads into a rather short 

 alimentary canal. 



All the anterior portion of the body is closely covered 

 with small backwardly curved spines. These are repre- 

 sented in fig. 11, which shows the margin of the body as 

 seen under a high power lens. On the posterior part of 

 the body these spines are either absent altogether or are 

 verv minute. 



