ORDER DECAPODA. 
157 
The following, forming the three next subgenera, have the 
fourth pair of feet, and then the third, longer than the others ; 
the intermediate antennae are excessively small, and scarcely 
bifid at the end ; their radical articulation is almost longitudi- 
nal. These animals are proper to hot countries. 
In the following the testa is solid, of a quadrilateral or tra- 
pezoid figure, wider in front. 
Gelasimus, Lat, Uca , Leach. 
The eyes terminate their pedicles in the manner of a little 
head; the third articulation of their external jaw-feet is in a 
transverse square ; the last segment of the tail of the males is 
almost semi-circular, that of the females is almost orbicular. 
The lateral antennae are proportionally longer and more nar- 
row than the same in the ocypodes. One of the claws, some- 
times the right, sometimes the left, (for this varies in indivi- 
duals of the same species) is usually much larger than the 
other ; the toes or fingers of the small one are often in the 
form of a spatula or spoon. 
Ocypode, Fab. 
The eyes extend into the major part of the length of their 
pedicles, and form a sort of knob ; the third articulation of 
the external jaw-feet is in a long square. The tail of the 
males is very narrow, with the last articulation in the form of 
an elongated triangle ; that of the females is oval. 
The claws are almost similar, strong, but short, with the 
forceps almost in the form of an inverted heart. Thus, as the 
etymology of the generic name announces, these Crustacea 
run with very great velocity ; it is so great, that a man on 
horseback would find some difficulty in keeping up with them. 
From this faculty they received the name of eques among the 
