168 ANCHID#. 
ISOPODA. ANCEIDA, 
ABERRANTIA. 
ANCEIDZ. 
Praniziens. Mitni Epwarps. 
Pranizide. Dana. 
Pranizade. Van BENEDEN. 
Decempedes. LATREILLE. 
(Males) Gnathides, Gnathonii, Gnathionii. LEacw. 
Ancéens. Mitne Epwanps. 
(Females) Praniziens prop. dites. Mityxe Epwarps 
Pranizide. Wartr. Dana. 
Tuk head has the first (or more probably the first and 
second) segments of the body fused with it; it is very 
large, and flattened, or dorsally concave in the males; 
quadrate or ovate, and of moderate size, in the females. 
The antenne are small or of moderate length, nearly 
equal, inserted widely apart, composed of a three-jointed 
peduncle and an articulated flagellum. The mouth is 
very anomalous in its structure, differing very greatly in 
the adult from the young, as well as in the opposite 
sexes of the same species. In the adult males the front 
of the head is armed with a very large pair of porrected 
mandibles; in the early stages the mouth in both sexes 
is suctorial in its character. The body is composed of 
only five segments, of which the three posterior are 
soldered together in the females, so as to form a large, 
oval mass. There are only five pairs of slender, simple 
legs. The pleon is of small size and narrow, but well 
developed, consisting of six segments, of which the last 
is small and triangular: each segment being provided on 
its ventral surface with a pair of delicate, membranous, 
biramous, squamiform appendages, which are entirely 
free, and not covered by a larger anterior pair or oper- 
culum. The terminal pair on each side form, with the 
