[51] DECAPODA FROM ALBATROSS DREDGINGS. 395 



thickened and transversely very strongly convex above at ba«e, but 

 not carinated, and posteriorly flattened or even slightly sulcated above. 

 The extreme tip is acute and spiniform, and the edges are clothed with 

 slender setse. 



The lamellae of the uropods are thin and lanceolate in outline. The 

 inner is only a little shorter than the sixth somite, less than a third as 

 broad as long, and stiffened in the middle by two slender rib-like thick- 

 enings, separated, on the dorsal surface, by a narrow sulcus. The outer 

 is about a half longer than the inner, about a fourth as broad as long, 

 and the narrow tip is prolonged far beyond the sharp spine in which 

 the thickened outer margin terminates, and from which a slender rib- 

 like thickening, with a narrow sulcus along its inner edge on the dorsal 

 surface, runs nearly parallel with the outer edge to the base of the la- 

 mella. 



The sternum of the first somite of the pleon is armed with a large 

 median laterally compressed dentiform process, which projects forward 

 in an acute point. The first pleopods are as large as the second, much 

 longer than the uropods, and the distal multiarticulate portion is more 

 than three times as long as the protopod and very slender. The pecu- 

 liar male appendage (petasma) is a thin, squarish plate attached by a 

 constricted base, below which there is a small oblong process standing 

 out at nearly right angles to the plane of the rest of the plate. The 

 plate itself, which is apparently carried in a nearly horizontal position, 

 in front and on the mesial side of the protopod to which it is attached, 

 is obliquely divided vertically or longitudinally by imperfect articula- 

 tions into three parts, of which the middle one is much the largest and 

 projects at the inner inferior angle in a large ovately-pointed process, 

 while the inner or distal of the three parts is narrow and has the lower 

 or posterior part of its free edge armed with minute hooked spines for 

 the attachment of the appendages of the opposite sides of the animal. 

 The outer rami of the second to the fifth pairs of pleopods are similar 

 to the single rami of the first pair. The inner ramus in the second pair 

 is very much more slender and considerably shorter than the outer, and 

 is furnished on the anterior side at base with two small and obtusely 

 terminated, hard, lamelliform processes. The inner rami of the third, 

 fourth, and fifth pairs are as in the first pair except that they are with- 

 out the lamelliform processes at base. 



The single /ma?e examined wants the eudojiods of the fourth and fifth 

 peneopods, except a part of one of the fourth pair, and is very nearly 

 like the males. The bases of the upper flagella ©f the antennulse are 

 perhaps a little more slender than in the males ; the male appendage 

 of the first pleopod is replaced by a minute styliform process : and in 

 place of the two plates at the distal end of the protopod of the second 

 pleopod, there is a single and much shorter plate. 



