DECAPODA. 
169 
widened form of their shell, and the shortness of their lateral antennje, 
apjjroaching the Mursiae and Calappe in their compressed hands, the 
upper edge of which resembles a crest ; but the third joint of their 
external foot-jaAVS form an elongated, narrow, and pointed triangle, 
without any apparent emargination, a character also observed in the 
Matutae and Leucosiae. 
The species * which served as the type of this division was 
confounded by Fabricius with the Calapp. It it as large as an 
ordinary Pagarus. The shell is yellowish, dotted with red, and 
the margins finely and unequally crenulated. The eyes are 
small and approximated, and the feet are traversed by red 
bands. Although the tail of the male has but five complete seg- 
ments, the traces of two others may still be discovered on the 
sides. This species is common at the Antilles. 
In our third section, or that of the Quadrilatera, the shell is 
nearly sqxiare or heart-shaped, the front generally prolonged, in- 
flected or much inclined, and forming a sort of clypeus. There 
are seven segments, distinctly marked across their whole breadth, 
in the tail of both sexes. The antennae are usually very short. 
The eyes of most of them are fixed on long or stout pedicles. 
Several live habitually on land, inhabiting holes excavated by them- 
selves ; others frequent fresh-water streams. They move with great 
swiftness f. 
A first division will comprise those in which the fourth joint of 
the external foot-jaws is inserted at the superior internal extremity of 
the preceding one, either in a short, truncated projection, or in a si- 
nus of the inner margin. They approach nearest to the Crabs proper. 
The shell of some is nearly square, or a trapezium, b\it not trans- 
verse, or almost in the form of a truncated heart. The ocular pedi- 
cles are short, and inserted either near the lateral and anterior angles 
of the shell, or more internally, but always at a considerable distance 
from the middle of the front. Here comes the 
Eriphxa, Lat. 
AVhere the lateral antennae are inserted between the ocular cavi- 
ties and the median antennae ; the nearly cordiform shell is truncated 
posteriorly, and the eyes are removed from its anterior angles. 
The coast of France furnishes a species — Cancer spinifronsy 
Fab.; Herbst., XI, 6.5 ; Desmar., Consider., XIV, 1, which is 
the Pagurus of Aldrovandus. The sides of its shell are fur- 
nished with five teeth, the second and third bifid. The front 
and claws are spiny ; the fingers black. 
* Hepatus fasciatus, Latr. ; Desmar., Considt^T., IX, 2 ; — Calappa anrjustata 
Fabr. ; Cancer princeps, Bose. ; Herbst., xxxvii, 2. See also his Cancer armadillus, 
VI, 42, 43. 
t I consider them, with respect to their hal)its and some of the characters of 
their organization, as being the furthest removed from the other Dccapoda ; they 
should be placed at one of the extremities of that order. 
