094 THE VOYAGE OF H.M.S. CHALLENGER. 



longer than inner, the latter with one spine, the former with three spines on the margin ; 

 second pair shorter than first, peduncle a little longer than rami, rami subequal, outer 

 with four spines on the margin, inner with a small one before the middle and a larger one 

 some way beyond the middle of the margin, at a point where the ramus is deeply notched 

 and narrowed, as in species of Ichnopus and some other genera. Third pair shorter than 

 second, peduncle outdrawn to a spine-tipped point on the inner side ; outer ramus longer 

 than inner, with a nail bearing an accessory thread near the tip on the outer side ; 

 adjoining the nail on the inner side is a spine with an accessory thread on the inner side. 

 The inner ramus has a cilium on the inner margin near the base, and one in a small slit 

 in its sharp apex. In the smaller specimen the details of spines and cilia showed some 

 variation ; for example, in the second uropods the outer ramus had two spines instead of 

 four, the inner had one instead of two. 



Telson small, reaching beyond the outdrawn sides of the sixth pleon-segment, 

 narrowing distally, carrying near the border on each side, beyond the middle, a long and 

 a short plumose cilium ; a little beyond these the slit begins, each terminal triangle 

 having in its blunt apex a cilium and a spine with an accessory thread rising nearer the 

 base of the spine than its apex. 



Lengt of larger specimen, with tail folded in and antennae bent down, less than a 

 quarter of an inch. 



Locality. — Station 1 4 9e, Greenland Harbour, Kerguelen, January 21, 1874; depth, 

 30 fathoms ; bottom, volcanic mud. Two specimens. Dredged. 



Station 149h, ofi" Cumberland Bay, Kerguelen, January 29, 1874; depth, 127 

 fathoms ; bottom, volcanic mud. One specimen. Dredged. 



I 



Remarks. — Through the kindness of Professor S. I. Smith, I have had the opportunity 

 of comparing this species with a specimen of Lysianassa kidderi, to which it shows some 

 resemblance, but the diiferences are very decisive. In that species the outer plate of the 

 maxillipeds is rounded ; in the first gnathopods the first joint is not bent ; in the second 

 gnathopods the wrist is not so long as in the present species ; the side-plates in the fourth 

 segment, and the first joints of the last three pairs of peraeopods, all differ strikingly ; the 

 telson is slightly excavated, not cleft. 



Genus Ambada, A. Boeck, 1870. 



For the original definition of this genus, see Note on Boeck, 1870 (p. 397). To 

 include the species here described, it must be modified by omitting the epithet " minima" 

 from the description of the inner plate of the first pair of maxilla3, and the epithet 

 " fissa " from the description of the telson. 



