TJie Kmixl i. 157 



tendency throughout the genus Leucon for the pseudorostrurn in the 

 male to be shorter than that in the female, hut the difference is 

 nowhere so extreme as in the sexes of L. longirostris, where the 

 produced part is more than a third of the length of the carapace 

 in the adult female, hut only a fifth of that length in the adult 

 male. 



The present spscies is unfortunately known only from a single 

 adult male specimen, which differs, so far as can he determined, from 

 the adult male of L. longirostris chiefly in the less-produced telsonic 

 segment and the proportions and armature of the uropods. 



The outline of the pseudorostrum was not made out with precision. 

 Integument squamose. Fifth pedigerous segment with procurved 

 ventral spines. Telsonic segment with produced portion much 

 instead of little shorter than the base. 



In the first antennae the third joint is shorter and much narrower 

 than the second, and carries two slightly feathered setre ; the four- 

 jointed principal fiagellum has the first joint nearly as long as the 

 three following combined, and carries on the outer margin approach- 

 ing the middle a fascicle of setae ; the one-jointed accessory flagelluni 

 is narrower than the first joint of the principal, but about equal to it 

 in length. The second antennae have the large last two joints of the 

 peduncle fringed with tufts of short setae, which till resolved by 

 high magnification look like fringed single setae. 



The upper lip is only slightly emarginate. The mandibles are 

 powerful. The palp of the first maxilhe ends in a single filament ; 

 the second are without setae on much of the inner margin. The first 

 maxillipeJs have a long seta on the second joint, third joint absent, 

 the fifth joint as long as the second and very setose, the sixth with 

 a strong plumose seta overhanging the small seventh joint, which is 

 tipped with a serrate spine. Second maxillipeds full-jointed ; the 

 third the same, its second joint broad, rather longer than the narrow 

 following joints combined, with strong spines or setae on the fore- 

 part of the apical border. 



First peneopods broken, the second joint much narrowed distally, 

 part of the margin fringed with setae. Second pair not elongate, 

 its second joint rather longer than the remaining joints combined, 

 the terminal joint not longer than the antepenultimate, fringed 

 with a longitudinal series of five spines, and having its blunt apex 

 armed with three long feathered seta-like spines. In these and the 

 much shorter following peraaopods the true third joint does not seem 

 to be distinct from the long second joint. In the last three pairs the 

 last four joints are all short, the last much the narrowest and tipped 



