INTRODUCTION. 
11 
: pairs, hence the name of the Order, Decapoda.^ The order 
! is divided into three suborders — Brachyura , Anomoura, and 
Macroura — the characters of which will be found under 
their respective heads. 
Suborder I. Brachyura, Latr . 
In the species of this division the abdomen is very 
slightly developed, and not employed to assist the animal 
in swimming ; it is folded under the body, and has no 
traces of appendages on the segment which precedes 
the last. The sternal plate is rather wide between all the 
legs, and is never linear : the surface of the carapace 
generally divided by grooves, for the most part correspond- 
ing with the muscular insertions, and which circumscribe 
regions of the stomach, heart, genital organs, branchiae, 
etc. The abdomen is generally very much wider in the 
females than in the males : in the latter it is more or less 
triangular, while in the former it is oval. 
Tribe 1. OXYRHYNCHITA, M. Bdw. 
Carapace contracted in front ; front part projecting, and 
forming generally a very prominent beak.f Mouth ap- 
* Ae/ca, ten. ; ttovs, 7 rodos, a foot. 
f Whence the name, — o£i»s, sharp ; pvyxos , a beak. 
