DECAPODA. 
203 
Their body is arcuated, almost gibbous, and of a less solid con- 
sistence than that of the preceding Crustacea. The front is always 
drawn out into a point, and most frequently so as to resemble a ros- 
trum or pointed lamina compressed and dentated along the edges. 
The antennae always project; the laterals are usually very long and 
resemble very fine setae ; the intermediaries of a great number ter- 
minate in three threads. The eyes are closely approximated. The 
external foot-jaws, more elongated and narrow than usual, resemble 
palpi or attennae. The mandibles of most of them are compressed 
and arcuated at the extremity. One of the first pairs of feet is fre- 
quently flexed upon itself. The segments of the tail are dilated or 
widened laterally. The external leaflet of its terminal fin is always 
divided in two by a suture, a character observed nowhere else ex- 
cept in the last Crustacea of the preceding section ; the azygous por- 
tion of the middle, or the seventh and last segment, is elongated, 
narrowed near the extremity, and provided above with ranges of 
small spines. The false feet, of which there are five pairs, are elon- 
gated and usually foliaceous. 
Immense numbers of these Crustacea are consumed in all parts 
of the world. Some species are even salted in order to preserve 
them. 
In some of them, the three first pairs of feet form a didactyle claAV, 
the length of which progressively augments, so that the third pair is 
the longest. Such are the 
Pen^ijs, Fab., 
AVhere there is no annular division in any of the joints of the 
feet. 
Their mandibular palpi are turned up and foliaceous. A little 
elliptical appendage may be seen at the base of the feet, a character 
which seems to approximate them to Pasiphaea, the last genus of this 
section, and to those of the following one. 
Some, all indigenous to Europe, on account of the shortness of the 
two threads of their intermediate antennae, form a first division. It 
contains the following species. 
P. sidcatus ; Pala>mon sidcatus, Oliv., Encyclop. ; Caramote, 
Rond., Hist. Nat. des Poiss., liv. xviii, chap. 7- Nine inches 
long; on the middle of the thorax a longitudinal carina bifur- 
cated at base, terminated by a projecting rostrum, compressed, 
Avith eleven teeth in its upper edge and one in the loAver ; a lon- 
gitudinal sulcus along each side of the carina. 
This species is very common in the Mediterranean and the 
object of considerable commerce. It is salted and shipped to 
the Levant. The P. trisidcatus, Leach, Make. Brit. XLII, 
which inhabits the coast of England, is perhaps a mere local 
variety of the sidcatus. Its thorax is trisulcate and the rostrum 
bidentate beneath. In the P. d’Orbigny , — Lat., Noiiv. Diet. 
d’Hist, Nat., Ed. II, article Pence, the carina is not sulcated. 
The intermediate antennae of others are terminated l)y long 
threads; they constitute our second division, to Avhich A\'e refer. 
