BEITISH ZOOPHYTES. 135 



1. H. viRiDis, Linnceus. Plate IX. G.g. 7. 

 Polypes verds (Trembley), Hydra viridissima (Pal.). 

 Hab. : Common. 



This species is distinguished by its grass-green 

 colour (produced by chlorophyll)^ and by possessing 

 6 — 10 tentacles shorter than the body. 



2. H. VULGARIS, Pallas. 



H. Grisea (Linn.), H. Brunnea {Templeton) . 

 Hab. : Common. 



This species is of an orange-brown colour, with 7 — 12 

 tentacles, which are rather longer than the body. 



3. H. puscA or OLiGAETis, Pallas. 

 H. verucosa (Temp.). 



Hab. : Still waters, rather rare. 



This species is of a brownish colour, and is noticeable 

 by having the lower part of the body attenuated, and 

 by possessing the power of extending the tentacles to 

 an enormous length. Ellis called it the " Long-armed 

 Fresh-water Polyp,^' 



4. H. ATTENUATA, Pallas. 

 H. pallens (Turt.). 



This species is probably a variety of H. vulgaris. 



