ISOPODA OP THE ' LIGHTNING ' AND OTHER EXPEDITIONS. 93 



Last peraeopods not furnished with plumose setse, or with a pectinated margin to the 

 hand, the whole limb of very simple structure. Basos long and narrow, naked ; 

 ischium very short ; meros four times as long, smooth, except that there are three or 

 four minute cilia terminally; carpus equal to two preceding joints combined, with only 

 four minute, slender, simple spines on the front margin, and three cilia at the end; 

 hand (i.prj) 5 ) shorter than wrist, smooth on the back, below with four slender slightly 

 serrated spines, alternately with four others which are simple and very small, at the 

 termination a cluster of about eight small spines round the base of the remarkably 

 long and very gradually attenuating finger. 



Length 15 millim., or three fifths of an inch. 



The single specimen here described was taken in 1263 fathoms, about one hundred 

 miles directly south of Eockall, ' Porcupine ' Expedition 1869. Station 22, lat. 56° 8' N., 

 long. 13° 34' W. 



The type has some curious irregular developments in one or two parts. The third 

 leg has a curious outgrowth, the upper portion of the basos being prolonged backwards 

 into a large double tooth (PL XVIII. fig. l.prp 3 ), the corresponding portion of the 

 opposite limb being entirely devoid of any such excrescence ; and the lateral spines 

 of the segment to which these limbs are attached are not symmetrically placed, the 

 spine on the same side as the excrescence being in an abnormal position. The first 

 legs also present another, though less conspicuous, want of uniformity, the wrist on one 

 side having the distal margin nearly straight on both faces of the hand, while the other 

 wrist has these margins somewhat deeply excavated. 



8. Apseudes grossimanus, Norman. (Plate XIX.) 

 Apseudes grossimanus, Norman, MS. Proc. Royal Soc. no. 125 (1870), p. 157. 



Frontal region armed with three porrected spines, the central or rostral spine long 

 and very acute, nearly two thirds as long as basal joint of upper antennas. 



Ocular processes short, bluntly rounded distally, and thus differing from those of all 

 the other species here described. 



Carapace very short and broad, with a strong tooth-like process on each side in 

 front of coalescence of the first perseon-segment. 



The perseon has a pair of lateral spine-like processes to each segment, and the 

 epimera of the second and two following legs also bear a spine at the hinder margin. 

 Beneath there is a spine on the epistoma (i. l) and on each perseon-segment, but in the 

 male the spine of the last segment is exchanged for a large male organ similar to 

 that described under A. simplicirostris. 



Pleon having the epimera produced outwardly into acute processes, which bend 

 backwards at the end ; beneath each has a central spine ; last segment equal in length 

 to four or five preceding, cylindrical, with two pairs of very small cilia on the back, and 

 a little tubercle on the median line between the bases of the uropods. 



vol. xn. — part iv. No. 3. — October, 18S6. q 



