Hydra (fracilis 



HISTOIRE DES HYDROÏDES 



Ayres 1856 p. 103. 



Agassiz,A. 1865 (c) p. 197, 225. 



313 



Hydra oligactis Pallas. 



Hydra ruhra 



Hydra ruhra Lewes. 



Houghton 1860 p. 2i 



