161 
the palm, there is a row of about 7 or 8 line setae along the inner 
margin and a small tuft towards the end of the outer margin ; 
the extremity is indistinctly separated from the rest of the dactylos 
and bears the terminal unguis and on the inner margin a small 
secondary tooth. 
The description just given and the figures 5 and 5 a of Plate 
xxiv. apply to the first thoracic leg of a fully grown male. In the 
female and probably also in young male the limb is of the same 
general shape, but the subchelate hand is less strongly developed, 
the propodos being much less swollen. 
The second thoracic leg (second gnathopod) (See Plate xxv., fig. 
1.) has the basos and ischios similar to those of the first leg but 
the fringe of setae on the anterior margin of the basos is much 
longer and contains about fifteen setae, and the tuft on the anterior 
margin of the ischios contains much stouter setae : the rneros is 
subtriangular, narrow at the base but does not overlap the carpus, 
the posterior edge bears about G or 7 stout seta and a number of 
others more slender, and there are similar tufts at the middle of 
the anterior margin and at the antero-distal angle. The carpus 
is not so short and triangular as in the first leg, the anterior 
margin is rather convex and bears a tuft of fine seta? at the antero- 
distal angle, the posterior margin is straight and bears six stout 
seta increasing in length distally. The propodos is subrectangular 
rather more than twice as long as broad, and is somewhat longer 
than the carpus ; the anterior margin is slightly curved and bears 
a few seta chiefly at the base of the dactylos, the posterior margin 
is straight and bears 5 or 6 stout spiniform seta? and a few slender 
ones. The dactylos is more than half as long as the propodos and 
is similar to that of the first pair of legs except that it is smaller 
and bears fewer seta upon it. Fig. 1 of Plate xxv. represents 
the third thoracic leg, but will do equally well for the second. 
The third thoracic leg (first per eiopod) (Plate xxv., fig. 1) is 
similar in all respects to the second, and is of about the same 
size. 
The fourth thoracic leg (second pereiopod) (Plate xxv., fig. 2) 
of the male is rather shorter than the two preceding legs and 
differs from them in a few small details. The basos and ischios 
are quite similar to those of the second and third legs, and are 
nearly as large ) the meros and carpus are similar but are shorter 
and stouter in proportion ; the propodos is also stouter and has 
the anterior margin strongly convex, the posterior margin is very 
short and bears two very stout spiniform seta placed side by side 
and defining a slightly concave palm ; the dactylos is strongly 
curved and bends back upon these two seta so as to form a 
powerful claw. It is only in the male that the fourth leg is thus 
modified, in the female it does not differ appreciably from the two 
preceding legs. 
