126 IOWA ACADEMY OF SCIENCES. 



When feeding, the tentacles are capable of unusual 

 extension until they seem a mere thread bearing notice- 

 ably large nematocysts, like beads strung on a string. 



The color is a deep bright coral red. most intense near 

 the distal end and seems to be distributed in chloroplast 

 like granules, as in H. viridis. It is apparently constant 

 and may be due to symbiotic algae. 



Since the waters of Echo lake contain large numbers of a 

 reddish Daphnia, and, thinking the question of their effect 

 on the color of the hydra would arise, a number of the 

 latter were taken alive, and fed for five weeks upon color- 

 less entomostraca, from Flathead lake, at the station 

 laboratory. While they did not seem to thrive, no notice- 

 able dimming of the color bodies was observed. 



A careful study of the literature and of hydra from 

 various localities will be made. Some eight species have 

 been described but only two are at present allowed. This 

 one seems to possess as much difference as is found between 

 the H. fusca and H. viridis and careful study should either 

 reduce them all to varieties or establish at least three 

 species. 



The striking color; the large size; the isolation of the 

 animals from related forms; the apparent division of the 

 body into a stalk and an enlarged gastric cavity, of about 

 equal length; the removal of gonads and buds beyond this 

 apparent division altogether seemed to make it worthy of 

 notice. Histological examination will be made and it is 

 believed the characters enumerated will prove constant 

 and new. 



