352 Trematodes Parasitic on British Fishes, [Sess. 



are small, the length of the first being about five mm. and of 

 the other about seven mm. 



Axine hellones is also provided with a large number of 

 minute suckers. In this species the body is flat and thin, 

 and very attenuated at the anterior extremity, becoming 

 gradually wider towards the posterior end, which is consider- 

 ably expanded and truncated, and has the truncated margin 

 crowded with minute suckers to the number of between fifty 

 and sixty. This species, which measures eight to ten mm. 

 in length, is parasitic on the gills of Sea-pike or Garfish 

 (Belone vulgaris Cuv.) 



Fam. GYEODACTYLID^.. 



Suh'Fam. Gyrodactylin.e. 



Diplectanum cequans Diesing is the only representative of 

 the Gyrodactylines I have seen. My son finds it common on 

 the gills of Bass (Labrax lupus) captured near Piel, Barrow- 

 in-Furness, Lancashire. It is a species about two mm. in 

 length, and is easily missed. Its shape is narrow and 

 elongate, but wider in the middle than at the ends. The 

 head, which has a truncated appearance, is armed with two 

 tolerably strong hooked spines on each side of a deeply 

 concave cleft, and this cleft is occupied by a process thickly 

 covered with minute prickles. 



This completes the enumeration of the Trematoda known 

 to me that are ectoparasitic on British fishes, but the number 

 might be easily augmented by a more careful examination of 

 the fishes captured off the coasts of the British Islands than I 

 have been able to bestow on them. 



In the following tabulated list the species referred to in 

 the preceding paper are arranged in alphabetical order ; and 

 as they have for the most part been recorded and figured in 

 Part III. of the Annual Keports of the Fishery Board for 

 Scotland for various years, the number and date of the 

 Eeport where the species is described, and the number of the 

 Plate containing a figure of it, are also given. Eleven species 



