78 CYAMID.E. 
labrum, rounded at the sides, but emarginate in front; 
a pair of mandibles, bifid and denticulated at the tip, 
but destitute of a palpus; a first pair of maxillz, com- 
posed of a single lobe; a second pair of maxille, much 
smaller than and inserted between the first pair, upon a 
common base, and each bearing a very minute two-pointed 
palpus; a labium, composed of two outer lobes and two 
inner minute ones (representing the four maxille), and 
a large maxillary outer labium, furnished with a pair of 
five-jointed palpi. 
Independent of the first articulation of the body, sol- 
dered to the head, the animal consists of six flattened 
segments, of which the middle ones are the broadest. 
They are separated widely from each other at the sides, 
and the last is terminated by a minute rudimental tail. 
The segment attached to the head supports on its under- 
side a pair of small legs, generally folded beneath the 
body, composed of four joints, terminated by a subcheli- 
form hand and a slender, curved finger. The following 
segment of the body bears a large and powerful pair of 
legs, although they possess one joint fewer than the 
hinder pairs. The hand is broad and flattened, and the 
finger curved and acute at the tip. The third and 
fourth segments of the body are destitute of legs, but 
their place is supplied by a pair of elongated, cylindrical, 
branchial appendages, in some species being as long as 
the legs themselves, generally turned over the back of the 
animal. Sometimes these are simple, but in other cases 
they are double, and at their base in the male is to 
be observed one or two small corneous points. In the 
female these two segments of the body bear two large 
ovigerous scales, affixed at the base of the four branchial 
appendages. The fifth, sixth, and seventh segments of 
the body respectively bear a pair of legs nearly similar in 
