ORDER DEC APOD A. 
149 
Such are, 
Podopiithalmus, Lam . 
The test is in the form of a transverse trapezium, more 
broad and straight in front, with a long tooth in the form of a 
spine, behind the ocular cavities. The claws are elongated, 
spiny, and similar to those of the majority of the species of the 
genus Lupa of Dr. Leach. The only living species known 
inhabits the coasts of the Isle of France, and those of the 
neighbouring seas. 
The ocular pedicles of the other Crustacea of this section 
are short, occupy but a very small portion of the transverse 
diameter of the testa, lodge in oval cavities, and resemble in 
general those of the ordinary crabs, with which those swim- 
ming Crustacea are almost insensibly connected. 
These Crustacea may be united into a single subgenus, 
that of, 
Portunus, Fab . 
Some species proper to the seas of the East Indies, such 
as the Admetus of Herbst, are distinguished from all the fol- 
lowing by their testa in the form of a transverse quadrilateral 
figure, narrowed posteriorly, and whose ocular cavities oc- 
cupy the anterior lateral angles. The eyes are thus distant 
one from the other, by an interval almost equalling the greatest 
breadth of the testa. The insertion of the lateral antennae is 
very remote from these cavities. 
Other species, whose testa is in the form of the segment of 
a circle, truncated posteriorly, and wider in the middle, are 
remarkable for the length of their claws, which is at least 
double that of the testa. Its sides present each nine teeth, 
of which the posterior one is much larger, in the form of a 
