3 74 
GAMMARLDiE. 
As soon as they are placed in a tank the animals of 
this species invariably dive to the bottom, and bury them- 
selves beneath the stones ; but should a piece of cork 
be placed upon the water, the animals will invariably 
return and crowd the under surface of the float. 
But although they may like the surface of the water 
their constant habitat is amongst the dark fuci which 
grow with such fertility between the tide-marks. Their 
habits are probably not so active as those of other 
species, since we find that their natatory appendages are 
often thickly covered with a species of Vaginicola , which 
Mr. Tuffen West considers may probably be V. crystal - 
Una. The following vignette illustrates this parasite. 
It is figured by M. Rentsch* as a species of Gregarina 
in his work on the Parasites of Gammarus ornatus. 
* Homoiogenesis. Erstes Heft. Gammarus ornatus und seine Schmarot- 
zer. Wismar, 1860, 4to. 
/ 
