190 HISTOEY OF BRITISH ZOOPHYTES. 



Professor Van der Hoven thinks otherwise ; and so does 

 Dr. Johnston, and so also, may we add, do we, and we have 

 seen more than one young one on the body at the same time, 

 not at Blainville's " point de jonction de la partie creuse et 

 de celle qui ne Test pas," but one of them nearer the tail, 

 and the other nearer the tentacula. 



2. HYDRA VULGARIS. 



Hab. Ponds and slowly running streams. 



This is about the same size as H. viridis, which it also 

 resembles in form, but it differs from it in colour, being of 

 an orange colour, or sometimes more of a brown or even 

 bright red tint, the brightness of the tint depending on the 

 nature of the food. The tentacula are rather more nume- 

 rous and longer than in the former. 



3. HYDRA ATTENUATA, Dr. Johnston. 



Hab. Ponds, Yetholm Loch, Roxburghshire, Dr. Johnston. 



" A larger animal than the former, and comparatively rare, 

 less sensible to external impressions, and of a more gracile 

 form. Its colour is a dilute olive-green, with paler tenta- 

 cula, which are considerably longer than the body, and 

 hang like silken threads in the water, waving to and fro, 

 without assuming that regular circular disposition which 

 they commonly do in 77. viridis." (Dr. Johnston?) 



