THE TREMATODE PARASITES OF FISHES. 



493 



examples of G. triglae. In consequence of the great variation which 

 undoubtedly occurs it is not thought advisable to regard this as a distinct 

 species. 



Rhipidocotyle viperae (van Ben.) {Vig. 4). 



I am identifying as this species a few Gasterostomes which were 

 obtained from the intestine of Trachinus draco. It is a form which 

 resembles G. triglae in general appearance, but which differs from it in 



KStrf 



Fig. 4. — Rhipidocotyle viperae. Ventral view x 85. C.B. Cinus-iioucli ; K.St. Ovary; 

 Ph. Pharj-nx ; T. Testes. G. Roberts del. 



having the genital glands arranged differently and in having a long and 

 slender cirrus-pouch which extends forward to near the middle of the 

 body. 



The length of mature specimens is •7-1-2 mm., and the maximum 

 breadth in the middle of the body is about -4 mm. The anterior end 

 is square-cut and the posterior end pointed. The whole surface of the 

 body is beset with minute spines. 



At the anterior end there is a shallow sucker measuring, in the largest 

 specimen, -13 mm. in diameter. Its musculature is very feebly developed. 

 Surmounting the sucker is a five-rayed fan-shaped structure, closely 



