204 
CRUSTACEA. 
PencBUs vionodon, Fab. ; Squilla muVca, Bout., Hist. Nat., p. 
81, wliicli inhabits the Indian Ocean. 
P. antennatus, Risso, Crust., II, 6, and P. mars. Id,, II, 5, 
also appear to belong to it. 
Stenopus, Lat. 
Distinguished from the Penaei by the transverse and annular 
divisions of the two penvdtimate joints of the four jjosterior feet. 
The entire body is soft ; the antennae and feet are long and slender, 
those of the third pair widest. 
But a single species is known. It was brought from the seas 
of New Holland by M. Peron and Lesueur. Olivier retains it 
in the genus Paloemon — Cancer seli ferus, L.; P Jiispidus, Oliv., 
Encyclop. and Atl. d’llist. Nat., CCCXIX, 2; Seba, Mus., HI, 
XXI, 6, 7 ; Herbst., XXXI, 3, where I first placed it. 
The remaining Carides, the intenaediatc antennae of many of 
which are terminated by three threads, have at most but two j airs 
of didactyle claws formed by the four anterior feet. 
A subgenus founded on a single species peculiar to North America, 
that of 
Atya, Leach, 
Is removed from all analogous Crustacea by an anomalous charac- 
ter. The force])S terminating the four claws is cleft down to its 
base, or seems to be composed of two fingers in the form of thongs 
united at their origin ; the preceding joint is crescent-shaped. The 
second pair is the largest. The intermediate antennae have but two 
threads. 
In all the following subgenera, the blades of the forceps originate 
at a certain distance from the base of the penvdtimate article, or of 
that which has the form of a hand ; the body or the part that pre- 
cedes it is not lunulated. 
We now have in the first instance those Carides whose feet are 
geiP'rally robust and not fdiform, and which have no appendage to 
their external base. Their l)ody is neither very soft nor greatly 
elongated. 
Among these svd)gencra, whose feet are deprived of this appen- 
dage, the three following lu'esent an insulated form with respect to 
their claws. 
Crangon, Fak. 
The two anterior claws, which are larger than the subsequent feet, 
have but a single tooth in place of the index or immoveable finger, 
and that which is moveable is bent and hooked. 
The superior or intermediate antennoe have but two threads. The 
second feet are folded up, and are more or less distinctly bifid or 
didactyle at their extremity ; neither of the joints is annvdatcd. The 
rostrum is very short. 
We do not separate the Egeon, Risso, or the Pontophilus, Leach, 
from Crangon. In the former, the last joint of the external foot- 
jaws is twice the length of the preceding one, while in tlie latter 
