production, voluntarily cad off with fudden vio¬ 
lence the offending member, and betaking them- 
felves to a rtate of retirement, await the formation of 
their new limb. Moll of the genus are very proli¬ 
fic animals. The female of the common Lobfter 
produces upwards of twelve thoufand eggs each 
time of laying. They are of a very voracious na¬ 
ture, and feed on animal as well as vegetable fub- 
rtances. The fpecics of cancer here reprefented is 
one of thofe which have the body naturally deftitutc 
of a fhelly covering; in confequence of which they 
never fail to take poffeffion of fuch vacant univalve 
fhells as happen to fuit their convenience; the body 
being immerfed in the {hell, while the claws remain 
exferted. Amongrt thefe parafitical or foft-bodied 
fpecies the two molt remarkable are the Cancer 
Bcrnardus and the Cancer Diogenes. It is the lat¬ 
ter of thefe which is figured on the prefent plate,; 
the firlt figure fhewing the animal in the {hell, the 
fecond reprefenting it diverted of its covering. It 
is generally found inhabiting the fliell of a Murex, 
Buccinum, Turbo, or Neritc, and has obtained the 
title of Diogenes from its refiding in this conveni¬ 
ent receptacle as that celebrated pfeudo-philofopher 
is reported to have done in his tub. 
I fhould not difmifs this article without obferving 
that the genus cancer affords a curious example of 
deviation from that, general fymmetry of parts fo 
confpicuous in moft other animals; in which the 
fhape of the body and limbs on one fide exactly 
correfponds to that of the other. Many of the 
Cancri, however, are furnifhed with a pair of chelae 
on 
