ECTOPARASITIC TREMATODES 291 



of the body, but again differs from it in the absence of the 

 vagina and several other characters. In short, the present 

 genus appears to me to combine several of the characters of the 

 Gyrodactylidae and the 3Ionocotylidœ. 



In conclusion it may be useful to formulate the diagnoses 

 of the new genus. 



" Body flat and elongated ; with a single posterior sucker, 

 the inner surface of which is divided by radial ridges into ten 

 areas, with one pair of chitinous hooks. Mouth at a short dis- 

 tance from the front end ; intestine bifurcated, simple. With 

 four eye-spots. Porus genitalis communis submarginal. Testes 

 two, one lying in front of the other. No vagina." 



