21 



\ 



processes; the first pair are in reality the supra-orbital spines which are nearly as long as the 

 eye-stalks and have several fine spiniform processes. Second pair project from the antero-lateral 

 angles; each process has about six long or very long branches, and on the distal part some 

 small spines. Third, pair a little behind second pair but much higher upwards on the vaulted 

 carapace, and these processes are probably homologous with the gastro-hepatic spines ; fourth 

 pair originate considerably behind the middle of the carapace somewhat above its lateral margin ; 

 each process of these two pairs has about four moderately long branches on its proximal third, 

 and some spines on the distal iDortion. Each of the five anterior abdominal segments (figs, i f 

 and I e) has three very long processes, one dorsal and one on each lateral margin, and these 

 processes are spiniferous and with branches towards their base; sixth segment has only the 

 dorsal process. Distal joint of the eye-stalks about half as long as the median line of the 

 carapace ; the eyes are large (fig. i d), considerably deeper than broad and placed not quite 

 vertical on the stalk. The antennular peduncles are not much shorter than the carapace, two- 

 jointed, with first joint more than three times as long as the second; upper flagellum about half 

 as long as the peduncle, two-jointed, while the lower flagellum is a mere knot. The antennal 

 squama (s^.) is very narrow and a little longer than first antennular joint, with the distal marginal 

 spine extremely long and projecting uncommonly remote from the end of the squama. Third 

 maxillipeds and all five pairs of thoracic legs with both endopod and exopod; in the two 

 posterior pairs the exopod is about twice as long as the endopod. All pleopods are very con- 

 spicuous, each consisting of a single, very oblong joint. The uropods (fig. i/) are long and 

 very slender; the peduncle has the outer angle produced into a long, spiniform process; the 

 exopod has the ciliated part of the outer margin a little more than twice as long as the naked 

 part, and at the end of the latter is found a somewhat long, spiniform process. The telson is 

 peculiarly shaped; its proximal third is broad, subrectangular, with a spine at each postero-lateral 

 angle; then it tapers rapidly to the middle, while its terminal part is again a little broader 

 and deeply divided into two branches; a pair of dorsal spines are seen considerably from the 

 end, and each branch has a small spine above and terminates in a very long and strong spine. — 

 Length without rostrum 2.5 — 3.2 mm. 



Remarks. — As already stated, the only valid specific differences between 5. semi- 

 nudus and S. corniailum hitherto found are in the structure of the male petasma. The males 

 of the two species are instantly separated by the shape and equipment of the lobus armatus, 

 which in S. seminudus is more slender with hooks alone the whole inner margin and no hook 

 near the distal end of the anterior side, while in S. corniculum the lobe is proximally consider- 

 ably thicker with about three conspicuous hooks along the proximal part of the inner margin, 

 some quite small hooks at the terminal margin, an extremely big hook on the front side near 

 the end, but no hooks alonsf the distal half of the inner margin to near the end. Furthermore 

 lobus connectens has in S. corniculuni. no hooks on its anterior side, the lobus terminalis a 

 somewhat other shape than in 5". seminudus^ and processus ventralis a higher number of teeth 

 at the distal margin. Judging from the size of adult specimens of both species S. corniculuin 

 is somewhat to considerably larger than 5'. semimidtts. 



A male specimen from the Bay of Bengal received from the Museum in Calcutta as 



