114 MESSES. NOEMAN AND STEBBING- ON THE 



portions are rounded at the extremities and crenated or serrulated ; the finger articu- 

 lates at the base of the cleft, and is exactly spear-shaped, with serrated edges. A 

 comparison of ir. ftp 5 with the figures of the hinder pereeopods of Alaotanais serrati- 

 spinosus (i.prp* and i.prp**) will at once give characters sufficient to distinguish these 

 species. 



The carapace, seen from above, is much narrower in front than behind, and has 

 a short rostrum ; the sides are very flexuous, and present two constrictions (u. c). 



The telson is shield-shaped ; the upper corners of the shield (that is, the sides of the 

 base of the telson) are very protuberant (11. pi. 



Length 5 millim. 



A single specimen, a female, taken in the ' Valorous ' Expedition, Station 9, lat. 59° 

 10' N., long. 50° 25' W., 1750 fathoms. 



3. Alaotanais LiEvisPiNosus, n. sp. (Plate XXIV. fig. n.) 



Male. The carapace is similar to that of Alaotanais serratispinosus ; the perseon- 

 segments bear the same proportion to each other, but they are not to the same extent 

 parallel-sided (n. d) ; viewed dorsally, a broad and deep constriction marks the separa- 

 tion of each from its successor, each segment being tumid laterally. The five first seg- 

 ments of the pleon are closely adpressed dorsally, with a very slight diminution in 

 width from the first to the last. The sixth segment is a little narrower than its prede- 

 cessors, and equal to two of them united in length. The uropoda are inserted about 

 midway of the length ; the remainder of the segment lying beyond them is much nar- 

 rowed, with a rounded termination. 



The upper antenna? (n. aa) have the first joint long and stout, with the usual row of 

 hairs on the outer side near the distal end ; the second joint is much shorter, but of 

 nearly equal thickness ; the third very short ; the flagellum demands attention. The 

 first joint, which is nearly as long as the last of the peduncle, has a remarkable protu- 

 berance on the underside, bearing a dense tuft of sensitive (olfactory X) cilia, which are 

 longer than the first joint of the peduncle ; the second joint is minute, and from its 

 distal termination spring two long olfactory organs. They are nearly four times as long 

 as the final articulation of the antenna, and are composed of many (apparently six) 

 cylindrical, smooth joints. The last joint still smaller, with one or two cilia. The lower 

 antennae are not unlike in character to those of L. serratispinosus. 



In a side view the cephalothorax is almost entirely hidden by the greatly developed 

 gnathopods (n. l), the general character of which is similar to those of Leptochelia 

 edwardsii. The basos is a substantial joint as broad as it is long, the next insignificant, 

 the following forms as it were a clasping-socket for the wrist, which is more than twice 

 as long as the basos, though not so broad ; in shape it is almost flask-like, the bent neck 

 fitting into the meros. A narrow neck at the base of the hand (n. gn l ) unites this por- 

 tion of the limb to the wrist ; the hand, with its greatly projected thumb, is consider- 



