16 Dr. W. NicoII on the 



Together they form the nucleu.s of a subfamily the nearest 

 relation of which appears to be not Stephanochasmus, as 

 Odhner remarkeil in the case of AcantJiopsolus oculatus, but 

 the Lepocreadiinje. It is impossible to include them in the 

 latter subfamily, but they are certainl}' nearly allied to it. 



Steringophorus farciger (Olsson) . 



The occurrence of this species in Lophi'us piscatorius^ as 

 recorded by Miss Lebour, is probably fortuitous, the parasites 

 being in all likelihood from some Pleuronectid fish swallowed 

 by the Angler. In British waters the species appears to be 

 entirely confined to the Pleuronectidas and to be one of their 

 most characteristic parasites, 



Zoogonoides vivtparus (Olsson). 



In British waters this species has hitherto only been found 

 in Pleuronectid fishe.', in which it occurs in great abundance. 

 I have found it quite as frequently and in as large numbers 

 in CalUonymus lyra and Anarrhichas lupus. In the North 

 Sea I have also found it fairly frequently in Pleuronectes 

 cynoglossus and Drepanopsetta platessoides , and in the Firth 

 of Clyde in PL jlesus and PL microcephalus. This makes a 

 total of nine British hosts for the species. 



The species is already so well known that no additional 

 description is necessary. It seems necessary to insist, how- 

 ever, that tlie diameter of the ventral sucker is not twice that 

 of the oral sucker, as both Odhner and Miss Lebour have it. 

 In my specimens the ratio is almost constantly 3 : 2, the 

 average sizes being '22 mm. and •145 mm. in a specimen of 

 •9 mm. length. 



With regard to the coloration, considerable variation seems 

 to occur. The general body-colour is lemon-yellow, with 

 numerous irregular splashes of brownish red, which is so 

 intense that when a number of parasites are viewed together 

 they appear to be of a dusky red colour. To me the para- 

 site has never appeared of a bright red colour, as Miss Lebour 

 describes it. Many specimens, however, seem to lack these 

 red patches, and the doubt has often occurred as to whether 

 the uniformly coloured specimens were really the same as 

 the others; but no structural differences could be detected. 



Van Beneden's Distomum callionym'i * is very probably 

 Zoogonoides viviparus. The figures which he gives show 

 some of the characteristic attitudes of that species, but other- 

 wise they are unrecognizable. 



* M^m. Acad. Roy. Belg. xxxviii. p. 53, pi. iv. fig. 3. 



