98 MESSES. NOEMAN AND STEBBING ON THE 



1. Sphtrapus malleolus, n. sp. (Plate XXII. figs, ii., in.) 



Rostrum short and obtusely pointed. Ophthalmic processes (in. d $ ) minute, shaped 

 like a baker's cap, and more easily seen from below (n. aa) th in from above. The 

 confluent segments are both wider than the head, and the second wider than the first ; 

 to the rear of these the animal tapers irregularly, the centre penieon-segment being 

 narrower than its neighbour, as is also the case in *S'. fiidcs, and the pleon tapers 

 more suddenly than the peraeon as far as the base of the sixth segment, the sides of 

 which diverge to the point of insertion of the uropods, and then suddenly converge to 

 a central and somewhat upturned, much produced, apical process (ill. pi.). Of the 

 peraeon-segments the last two are the shortest. The first five segments of the pleon are 

 nearly equal in length to one another ; only the second has lateral spine-like processes, 

 but here they are large, produced, and very conspicuous. 



The upper antennae (ii. aa) have the basal joint large, in the male stout, shorter 

 than the cephalic plate, in the female dilated at the base, longer than the cephalic 

 plate, in both ciliated on the margins; the second joint is short, dilated distally ; the 

 third is about half the length and breadth of the second ; the flagellum consists of one 

 long succeeded by four short articulations; the secondary appendage is rudimentary, 

 and represented by only one minute articulation. 



The lower antennae have the basal joint as broad as it is long, the three following 

 joints short, the fifth long and slender, carrying on the outer side two pear-shaped 

 vesicles; the flagellum is three-jointed, the second and third joints furnished with 

 long cilia. 



The first gnathopods (ii. r/«') have the soldered coxal portion folded beneath; the 

 bases broad and short, the ischium wanting; the meros narrow at the base, then 

 dilated, and ending in a point; the carpus in the male is a little longer than the meros, 

 which it overlaps; it is pointed distally, its sinuous margins are nearly parallel; upon 

 it the huge hand is set hammer-wise. In shape the hand is roughly triangular ; a line 

 from the base of the finger to the stout horny thumb may be considered the base of the 

 triangle ; along this (palm) margin is set a row of flat little teeth, all but one or two 

 of them lying closely side by side ; one of the sides of the triangle runs from the 

 thumb-nail backwards, receiving the wrist in a sinuosity about the middle, the remaining 

 side is formed by the curved line running from the liinder extremity of the last-described 

 side to the base of the finger; the finger, which is short and stumpy, with a nail like 

 the thumb-nail, doubles closely down upon the palm. In the female (in. c/«') the 

 wrist is considerably longer than in the male, and is of the same breadth at both ends, 

 but has a narrow neck near its base ; the hand in this sex is attached to the wrist by 

 the apex of the triangle; the thumb is a long process projecting from the base of the 

 triangle, and causing the finger to project in like manner, and the hand is thus of 

 very different form from that of the male, being ovate ; the inner margins of both 

 thumb and finger are irregular ; the thumb is truncate and has the horny nail set close 



