CRAB. 
494. 
genera of Murex and Bucciniim. Its general 
colour is pale red. 
, Among the smaller kind of fresh-water Cancri 
the Cancer stagnalis is the chief : this is an insect 
of great elegance, and is occasionally found in 
small stagnant waters, at first sight rather suggest- 
ing the idea of the larva of some kind of Dytiscus 
than of a species of Cancer. Its length is about 
an inch and half, and its colour pale blueish green : 
the male is furnished with a pair of strong hooked 
jaws or processes of which the female is destitute: 
this latter is generally distinguished by its ovarium, 
of a pointed shape and of a brownish colour. 
In clear springs, ponds, &c. may be frequently 
observed a species much smaller than the former, 
viz. the Cancer Palex of Linnasus. This measures 
about half an inch in length, and is of a livid brown 
colour; it generally swims with considerable ce- 
lerity but with a vertiginous kind of motion, and 
commonly on one side. 
I must not dismiss the genus Cancer without 
observing that, by one of those revolutions in 
science which sometimes take place, this whole 
genus is, at present, in danger of being expelled 
from the class of Insects, and of ranking in a 
separate department. 
