GYRODACTYLID^. 51 



non of alternate generation or of digenesis, as Von Siebold supposes, 

 but a simple viviparous reproduction." 



Genera. — Gyrodactylus, Nordmann ; Dactylogyrus, Diesing ; 

 Galceostoma, Van Beneden; Tetraonchus, Diesing ; Diplectanum, 

 Diesing. 



