322 A HISTORY OF EECENT 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 Sphyra/pus 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 pi eon. 



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. Tanaidce. 



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 perason and pleon are without 

 spiny armature. The pleon is seldom narrower and some- 

 times broader than the pereeon. The first antennae 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 

 antennae 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 

 maxillas have one incisive lobe and a one-jointed 'palp' 

 usually ending in two setae. The second maxillae 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. 



