204. ANCEIDA. 
the male is somewhat quadrate in form, having the 
anterior margin more prominent than in the preceding 
species; the upper surface of the head is more broadly 
and regularly concave, and the mandibles are scarcely 
more than one-third of the length of the head; they are 
curved, with the tip produced into a sharp tooth, below 
which the inner margin is armed with about eight small, 
sharp teeth. When shut, these mandibles project but a 
small distance beyond the crenated fore margin of the 
head. The antenne are about the length of the head, the 
upper ones being shorter and considerably more slender 
than the lower pair; the latter pair are composed of 
two strong basal joints, followed by a third joint, rather 
longer than the second; the fourth is still longer, rather 
thickened at the tip, where it is armed with several 
setee, and is followed by an eight-jointed flagellum. 
The upper pair scarcely extends beyond the base of 
the flagellum of the lower pair. The outer foot-jaws 
are formed of a large basal joint, somewhat ovate-trun- 
cate in form, affixed transversely by its base near the 
posterior angles of the underside of the head; the re- 
mainder of the organ consists of four joints, forming a 
broad, somewhat oval, flattened mass, affixed so as to 
form an angle on the basal joint; the first of these 
four joints is small, and furnished with a strong seta 
on its inner angle, whilst the remaining joints are 
densely ciliated along the margin. The inner pair of 
foot-jaws differs considerably from the same organs in 
A. mazillaris, being formed of a large white, tumid, semi- 
circular basal joint, having a small lobe at its inner 
extremity, followed by four joints excessively delicate 
and thin in their texture, and furnished on the outside 
with long obliquely deflexed sete. The head is sepa- 
rated from the first distinct segment. of the body by a 
ee 
