726 ME. s. KEMP ON DECAPOD [June 15, 



each of the outer angles ; in another only a single spine is found 

 in this position. 



The petasma (PI. LXXV. fig. 4) is a comparatively simple 

 structiire and is remarkably small for such a large species. The 

 thelycum (PI. LXXV. fig. 5) bears some resemblance to that of 

 G. cdicei. The triangular plate between the bases of the third pair 

 of pereiopods is not traceable in one of the females examined. 



This species occupies a somewhat primitive position in the 

 genus Gennadas. It is readily distinguished from all forms 

 hitherto described, by the use of the characters suggested by 

 Bouvier, by the prominent spine on the first abdominal sternum, 

 and by the extremely nari-ow apex of the antennal scale. 



Gennadas bouvieri*, sp. n, (Plate LXXIY. figs. 1-4; Plate 

 LXXV. figs. 6 & 7.) 



St. 206. W. of Manila. 17° 54' K^ 1170 14' e. Trawl. 



2100 fathoms. One female, 28 mm. 

 St. 220. N. of New Guinea. 0° 42' S., 147° E. Trawl. 1100 

 fathoms. Two females, 26 and 28 mm. 



The rostral ci"est (PI. LXXIY. fig. 1) is of much the same foi-m 

 as in G. parvus ; the apical and dorsal teeth are, howevei-, rather 

 less prominent and the inferior margin is not so decidedly convex. 

 The carapace is dorsally carinate throughout its length. Both 

 the antennary and infra-antennary angles are acute and strongly 

 pronounced, and the branchiostegal spine is distinct though very 

 small. The cervical and post-cervical grooves are very closely 

 approximate dorsally, the distance between them is scarcely more 

 than one-fifth the distance from the post-cervical groove to the 

 hinder margin of the carapace. 



The second joint of the antennular peduncle, measured dorsally, 

 is about the same length as the ultimate joint. The antennal 

 scale (PI. LXXIY. fig. 2), which is rather narrower distally than 

 in G. parvus, is a trifle less than three and a half times as long as 

 wide. The outer margin terminates in a short spine which 

 extends slightly beyond the apex of the lamella. 



The ultimate joint of the mandibular palp (PI. LXXIY. fig. 3) 

 is rather shorter than the greatest width of the basal joint. In the 

 second maxilla the anterior lobe of the internal lacinia is slightly 

 constricted behind its apex and is rather narrower than the 

 adjacent and similarly constricted lobe of the external lacinia,. 

 The anterior lobe of the latter lacinia is one and a half times the 

 width of the posterior lobe. The endopod is produced to a 

 narrow apex furnished with two terminal setfe and four curved 

 spines on the dorsal aspect. The endopod of the first maxillipede 

 is about the same length as the exopod. The third joint is almost 

 twice the length of the second ; the fourth joint, though small, is 

 rather more evident than in the preceding species. The basal 

 joint bears three curved spines on its inner distal margin. The 



* Professor E. L. Bouvier. 



