ORDER AMPIIIPODA. 
209 
Atylus, Leach. [Atylus carinatus, Leach.) 
All those which succeed, have the upper antennae as long, or 
longer than the lower, and the head does not advance in the 
manner of a muzzle. 
Here, as in the five following genera of Dr. Leach, the 
peduncle of the antennae is formed of three articulations. 
Some present, in their superior antennae, a character unique 
in this order; the interior extremity of the third articulation 
of their peduncle has a small articulated thread. It dis- 
tinguishes 
Gammarus, (proper) Latr. 
The four anterior feet are in the form of little claws, with the 
talon, or mobile finger, folded underneath. ( Cancer pulex, 
Linn.) 
The antennae of the following, are, as well as in all other 
amphipods, simple, or without appendages. 
Melita, Leach, 
Have the second feet terminated in the males, by a large 
compressed pincer, with the talon folded under its internal 
face ; the antennae are almost of equal length ; the posterior 
extremity of the body presents, on each side, a small foliaceous 
plate. ( Cancer palmatus, Montagu.) 
M.era, Leach, 
Whose second feet are likewise terminated in the males, by a 
large compressed pincer, but the talon is folded back on its 
infeiior edge, and is not concealed; the upper antennae are 
longer than the lower, and the posterior extremity of the body 
presents no foliaceous lamina. [Cancer gammarus grossi- 
manus , Montagu.) 
Ampithoe, Leach, 
In which the four anterior feet are nearly identical in both 
VOL. XIII. 1> 
