THE TKEMATODE PARASITES OF FISHES, 477 



Sub-Family Stephanochasminae. 



Genus STEPHANOCHASMUS Looss. 



Stephanochasmus caducus Looss var. lusci. 



Numerous young specimens of a parasite which I can only with some 

 doubt identify as this species w^ere taken on two occasions from the 

 duodenum and pyloric caeca of Gadus luscus. A single immature speci- 

 men was also found in the caeca of Gadus tnmutus. 



They measure 1-5-3 mm. in length, and most of those over 2 mm. 

 contained ova. The cephalic spines are arranged in two rows of 25 each, 

 and those of the anterior row are shorter than those of the posterior row, 

 •019 mm. and '021 mm. respectively. In a 3 mm. species the oral sucker 

 has a diameter of -12 mm. and the ventral -14 mm. The latter is situated 

 •63 mm. from the anterior end. The prepharynx is -21 mm. long, and 

 the pharynx measures -1 x -08 mm. 



The cirrus-pouch extends -49 mm. behind the ventral sucker. The 

 vagina joins it behind the sucker, and the genital sinus is -2 mm. long. 

 The ovary, testes and yolk glands are situated as described by Looss, but 

 the yolk glands extend forward a short distance in front of the end of the 

 cirrus-pouch. The few ova measure -066 x -036 mm. 



The chief respects in which these specimens differ from Looss"s de- 

 scription (1901, p. 603) are the number and size of the cephalic spines, 

 the position of the ventral sucker, the inequality of the suckers and the 

 greater extent of the yolk glands. It seems possible to ascribe the first 

 two of these to difference in age and size of the specimens (Looss's de- 

 scription was from specimens over 4 mm. long). The other two features, 

 together with the difference in number of the cephalic spines, do not 

 seem of sufficient importance to warrant establishing a new species, but 

 it seems advisable to regard this form as a distinct variety. 



It is interesting to note that the specimen obtained by Miss Lebour 

 (1908, p. 36) from the whiting {Gadus tnerlangus) does not entirely agree 

 with Looss's description of S. caducus. The suckers are nearly twice as 

 great as those of Looss's form. The yolk glands are more extensive and 

 the eggs are larger. It is possible that this may represent a third variety 

 of the same species. 



Stephanochasmus cesticillus (Molin). 

 Looss, 1901, pp. 598-9. 

 Four specimens of this parasite were collected from the stomach and 

 intestine of Zeus faher. This is the first and only time this parasite has 



