O22 A HISTORY OF RECENT CRUSTACEA 
appearance of the first gnathopods, especially in the male, 
in which sex the huge hand is set on at right angles to 
the preceding handle-like joint. Like Sphyrapus tudes, of 
the same authors, it has been taken off the west of Ireland. 
From the latter species it is distinguished by the great 
extension of the lateral processes on the second segment 
of the pleon. 
In both of these species there are exopods on both 
pairs of gnathopods, but, according to Sars, they are absent 
from the second pair in his species, anomalus and serratus. 
Family 2.—Tanaidee. 
The body is nearly parallel-sided, the carapace being 
truncate in front or with a minute rostrum, with or without 
ocular lobes and eyes. The perzeon and pleon are without 
spiny armature. The pleon is seldom narrower and some- 
times broader than the perzeon. The first antenne are 
contiguous, with a single flagellum, which is rudimentary 
or sometimes wanting or rarely well developed in the 
female, but multiarticulate in the male. The second 
antenne are smaller than the first and below them, with- 
out scale, and with the flagellum rudimentary or rarely 
well developed. The mandibles have no ‘palp.’ The first 
maxillz have one incisive lobe and a one-jointed ‘palp’ 
usually ending in two sete. The second maxilla form 
minute rudimentary unarmed lobules. The maxillipeds 
are fused at the base, and usually have a narrow falci- 
form epipod. The masticatory organs are, however, often 
evanescent in the adult male. The gnathopods are with- 
out exopods. In the first pair the second joint is large 
and tumid, and in the adult male the sixth joint or hand 
becomes so much developed that it seems to crowd the 
mouth-organs out of existence. The second gnathopods 
are ambulatory like the following limbs. The pleopods 
have two short setiferous branches, or are rarely absent. 
The uropods are either simple or furnished with two fila- 
ments, of which the outer is always short, having one, two, 
or at most three, joints. 
