SPHHROMA. 403 
outer margin is affixed a triarticulated appendage.* The 
inner maxillz consist of two nearly equal curved blades, 
the inner of which is ciliated at the tip, and the outer 
armed with strong spines. The outer maxille are ter- 
minated by three oval, very delicate plates, strongly 
ciliated. The foot-jaws are large and strong, and close 
the mouth ; they are composed of a strong, basal joint, 
followed by a small joint, and are furnished with a large 
triangular inner lobe, and terminated by four strong 
_ joints of nearly equal length, but gradually diminishing 
in thickness, and strongly ciliated. In some of the 
species these four joints are internally produced into 
a large lobe; the lower lip is rounded at the sides 
and very deeply notched in the middle of the fore- 
margin. 
The first segment of the body is larger than the fol- 
lowing, and strongly produced backwards at its posterior 
lateral angles; the six following segments are marked at 
the sides with an impressed oblique line indicating the 
coxze er epimeral base of the legs; the seventh segment 
of the body is very short, and does not extend outwardly 
so far as the first segment of the tail (pleon), which is 
marked on each side with two transverse strize, which do 
not unite in the middle of the back, but which represent 
three segments coalesced together. The terminal joint is 
large, and marked at its base with a rather deep transverse 
channel. The legs are of nearly equal size; they are 
terminated by a bifid finger. The tail-plates (pleopoda) 
consist of six pairs, five folding obliquely upon each 
other, and received in a deep excavation on the underside 
of the tail, of which the two last are furnished with bran- 
* Savigny (Egypte Crust., pl. 12, f. 1i,) represents the middle joint as 
divided into two, probably arising from the appendage having been twisted 
in this part in the specimen dissected by him. 
DD2 
