483 



long when outstretched. Cuticle smooth. Ventral sucker one and 

 one half times as broad as oral sucker. Caeca originate immediately 

 behind pharynx and extend into posterior end. Ovary and testes 

 at centre of body, close together, ovary in advance. Uterus in trans- 

 verse folds from ovary to ventral sucker. Genital opening below 

 posterior end of pharynx. Vitellaria lateral, from half way between 

 ventral sucker and ovary to a short distance from the posterior end. 

 Laurer's canal opening in mid-dorsal line. Posterior excretory 

 vessel forking behind second testis. Is allied to but distinct from 

 the genus Azygia. 



14) Xenodistomum melanocystis. 



In dark, fibrous cysts in innerwall of stomach oî Lophius pisca- 

 torius L. (Goose-fish). 



New genus and species: ^évoç, stranger; (xélag, black; y.vaTig, 

 bladder. Cysts 3 in diameter, worm 5,5X1. Cuticle smooth. Ven- 

 tral sucker little larger than oral. Posterior half tapering. Resemb- 

 les preceding species but is immature with rudiments of genital 

 glands and ducts. 



15) Derogenes various O. F. Müller. 



Mouth, oesophagus, stomach. 



Salmo salar L. (Salmon). 



Gadus callarias L. (Cod). 



Melano grammus aeglifinus L. (Haddock). 



Pollachius vireus L. (Pollack). 



Clupea harengus L. (Herring). 



Osmerus mordax Mit. (Smelt). 



Sehastes marinus L. (Rose-fish). 



Anguilla anguilla L. (Eel). 



Cryptacanthodes maculatus Storer (Wry-mouth). 



Acanthocottus scorpius L. (Sculpin) . 



Hemitripterus americanus Gmelin (Sea-Raven). 



Lophius piscatorius L. (Goose-fish). 



Hippoglossus hippoglossus L. (Halibut). 



Limanda ferruginea Storer (Sand Dab). 



Platysomatichthys hippoglossoides Walb. (Greenland Turbot). 



Hippoglossoides platessoides Fab. (Rough Dab). 



Commonest of all distomes of fishes. 2,75X0,75. Ventral sucker 

 1,5 times as broad as oral sucker, situated about the middle. Caeca 

 branch from pharynx and reach to posterior end. Testes oblique, 

 behind ventral sucker. Ovary slighthy to one side behind then, and 

 vitellaria two small masses behind it. Uterus filling all the body. 



32* 



