OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 283 



species. The list comprises two species originally described by S. I. Smith as Amalo- 

 penseus elegans (1882) and A. valens (1884), and a third which Smith described, 

 also in 1884, as Benthesicymus 1 carinatus. 



In this genus the male petasma or " andricum," where, as in many cases, it has 

 been carefully figured, appears to be very serviceable for specific distinction. 



Gennadas hempi, n. sp. 



Plate XXVII. 



In spite of its mutilated condition, the specimen here described seems properly 

 separable from other known species. It makes a near approach to G. elegans in the 

 outlines of the carapace, in the proportions of the third peraeopod, and in having 

 only one pair of spines at apex of the strongly sulcate telson. But there are several 

 differences. The second joint of the first antennae is not shorter than the third. 

 The scale of the second antennae is produced well beyond the little lateral tooth. 

 The curved spines behind the narrow apical process of the endopod in the second 

 maxilla are four in number, two much more curved than the others. In the first 

 maxilliped the exopod is shorter instead of longer than the endopod. The petasma 

 is nearer to that of G. calmani, Kemp, than any other that has been figured, but is 

 more truncate ; the inner opposed margins are straight, lined with a multitude of 

 little coupling hooks. The first pleon segment is ventrally produced to a sharp point, 

 and in G. calmani it is said to carry " a very strong, sharply pointed spine," which 

 may mean the same thing. The apex of the telson is truncate, not rounded, with 

 five plumose setae between the single pair of spines, as in G. bouvieri, Kemp. 

 G. calmani has (whether invariably or not is uncertain) eleven setae between two 

 pairs of spines, subject to the variation of a single pair. It agrees with our species 

 in the four curved spines of the second maxilla, but differs in the longer exopod of 

 the first maxilliped. Both species belong to the group which have the fourth joint 

 of the third peraeopod longer than the fifth, and in both the fingers of the chela in 

 that limb are subequal to the palm, but in G. calmani the chela is half as long as 

 the fifth joint, whereas in the new species it is more than half as long. Other differ- 

 ences between these closely connected species will be found in the two pairs of 

 antennae. In the first pair G. calmani has the second joint not equal to the third, 

 but "fully three-quarters the length" of it; in the second pair the scale is scarcely 

 at all produced beyond the lateral tooth. Through the condition of the respective 

 specimens many features are not available for comparison. As described and figured 

 by Bate for his G. parvus, the second pleopods have at the apex of the peduncle 

 on the inner side two membranous leaf-like appendages. In Bate's figure these 

 show setules on the outer margin distally. In our species one of these is somewhat 

 bean-shaped, without any armature ; the other, lying between it and the endopod, 

 is oval, having much of its inner and distal margin fringed with little, somewhat 

 curved, spinules. One of the stations at which G. parvus was obtained by the 



