402 SPH HROMIDA. 
The body is of a more or less oval form, very convex, 
and rounded at each end, thus differing from the Cymo- 
thoz, which have the anterior part of the body much 
narrowed. The head is broad and vertical, having a 
frontal elevated transverse ridge which is continuous with 
the lateral margin of the body. The eyes are very wide 
apart, placed at the superior lateral angles of the head, 
and received into an emargination on each side of the 
first segment of the body. The antenne are inserted close 
together in the middle of the anterior surface, on each 
side of a small frontal prominence which is joined below 
to the epistome; they fall back and are protected (when 
unemployed) by being lodged within a groove beneath 
the lateral margin of the head and anterior segment of 
the body; the upper or inner pair are affixed at the sides 
of a small triangular frontal prominence, and have a very 
broad and flattened, nearly quadrate, basal joint, fol- 
lowed by a second smaller one; the third as long as the 
second, thin and cylindrical, followed by a short, slender, 
articulated flagellum, consisting of about a dozen articuli. 
The lower or outer antenne are considerably longer than 
the upper, with the basal portion composed of four 
moderately thickened joints and a multiarticulate flagel- 
lum. The epistome is generally quite distinct from the 
upper lip, and is produced above into a point, nearly 
meeting the point of the upper triangular piece above 
mentioned; on its lower edge it is very deeply emarginate, 
receiving the base of the upper lip or labrum, of which 
the anterior margin is nearly straight. The mandibles 
are strong and horny, strongly angulated at the ex- 
tremity, and terminated in that part by two slender 
denticulated teeth, below which, on the inner margin, is 
a large and strong molar tooth. Near the middle of the 
