348 THE AUSTRALIAN HYDROMEDUS.E, 



with the budding in other Hydromedusae, which form colonies. 

 The fact, that in the case of the Hydridre, these buds become 

 detached, and so the Polyp remains solitary, cannot be considered 

 as sufficient reason for placing the Hydridae in a separate Suborder. 

 We would have to make a Suborder for Myriothela also, if we did 

 that for Hydra, for Myriothela also remains solitary. Glaus and 

 others consider the Hydridae as a Family of the Hydromedusse 



only. 



1. GENUS HYDRA. Linne. 



Non-sexual propagation by budding. This genus has been 

 studied particularly by Kleinenberg (1), F. E. Schulze (2), Parker 

 (3), and Jickeli (4.) 



There are no sub-epithelial muscular cells nor Gariglia, or 

 epithelial sensitive cells. 



The histological structure is simpler than in any other Hydroid. 



The " Epithelmuskelzelle " is the predominent element. 



1. HYDRA OLIGACTIS. Pallas. 

 Bale (5) refers a Hydra which is found in the vicinity of 

 Melbourne, to this species. 



2. HYDRA FUSCA. Linn<S (?). 



T. Parker, (6) of Dunedin, N.Z., gives an excellent account of 

 the Histology of this species, but it does not appear from his 

 paper whether he got his material from Europe or New Zealand. 



3. HYDRA VIRIDIS. Linne. 



Coughtrey (7) refers a Hydra, found in New Zealand, to this 

 species. 



(1.) Nicholaus Kleinenberg, Hydra. Leipzig, 1S72. 



(2.) F. E. Schulze. Cordylophora lacustris. Leipzig, 1871. 



(3.) Parker. On the Histology of Hydra fusca. Proceedings of the Royal 

 Society, No. 200, 1880. 



(4.) Jickeli. Her Ban der Hydroidpolypen. I. Morphologisches Jahrbuch. 

 Band, VIII. Seite, 373. 



(5). W. M. Bale. Catalogue of the Australian 1 1 //timid Zoophytes, p. 187. 



(6.) T. Parker. On the Histology of Jfijdra fusca. Proceedings of the 

 Royal Society, No. 200, 1880. 



(7. ) Coughtrey. On New Zealand Hydroida. Annals and Magazine of 

 Natural History, 4th Series, Vol. XVII., p. 24. 



