ORDO HYDROMEDUS.E. 



Cams, 1SG3. 



POLYPOMEDUS.E, without gastral filaments. The polypoid forms rarely 

 solitary ; they mostly form colonies, and then always possess a chitinous or 

 calcareous skeleton. The trophosomes are destitute of an cesaphagal tube. 

 Some of the tubes are often converted into mouth and tentacleless sexual or 

 defensive zooids. The medusoid forms are cycloneur. (2) (23) (-13) (44) (59) 

 (90) (91) (101) (135). 



I. SUB-OEDO.-HYDROPOLYPIN^;. 



V. Lendenfeld, 1884. 



Polyps, or polyp colonies, the sexual products of which are matured in the 

 ordinary alimentary polyp or in zooids which are converted into mouthless 

 generative zooids, polypostyles. (4) (20) (29) (54) (65) (87) (130) (131). 



I.-Fainilia HYDRIDJE. 



Huxley, 1856. 



Solitary polyps ; the sexual products are matured in the gastral wall. 

 Without hydrothecie. 



1. Genus HYDRA. Linne. 



Nonsexual propagation by budding. (49) (53) (55) (65), (66) I 301, (70) 

 (75) (79) (80) (107) (114). 



1. Hydra obigactis. Pallas. (9) 187, (62) 315, (67) 124, (92) 34s. 



Hydra fnsca (15) 1320. 

 Long-armed fresh-water polyps (38) 16. 

 South-east Australia (Victoria). 



2. Hydra viridis. V. Linne. (26) 24, (45) 1320, (67) 121, (92) 348. 



Hydra viridissima (113) 31. 

 Polype verda (127) 22. 

 New Zealand. 



