156 
CLASS CRUSTACEA. 
widened in front, as well as by their ocular pedicles, which, 
like those of podophthalmus, are inserted near the middle of 
the front, long, slender, and reaching the anterior angles ; the 
claws of the males are long and cylindrical. Such are 
Gonoplax, Leacli, 
Our seas furnish two species, Cancer angulatus, Linn., and 
Cancer rhombo'ides, Ejusd. ; the principal difference between 
which is, that the former has spines at its anterior and poste- 
rior angles, the letter at the anterior only. 
In the second division of quadrilatera, the fourth articulation 
of the external jaw-feet, or of those which cover interiorly 
the other parts of the mouth, is inserted at the middle of the 
end of the preceding articulation, or more externally. 
Sometimes the testa is trapezoid or ovoid, or in the form of 
a heart, truncated posteriorly ; the ocular pedicles, inserted at 
a little distance from the middle of its anterior edge, extend 
as far as the anterior angles, or even go beyond them. 
In commencing with those whose testa has the form of a 
transverse four-sided figure, widened in front and narrowed 
behind, or has the form of an egg, we first find 
Macrophthalmus, Leach. 
As well as in gonoplax, the testa is trapezoid, the claws are 
long and narrow ; the ocular pedicles are slender, elongated, 
and lodged in a groove, under the anterior edge of the testa ; 
the first articulation of the intermediate antenna; is rather 
transverse than longitudinal, and the two divisions which ter- 
minate it are very distinct and of middle size ; the external 
jaw-feet are approximate inferiorly at the internal edge, with- 
out vacancy between them ; and their third articulation is 
transverse. 
