30 
THE VOYAGE OF H.M.S. CHALLENGER. 
Habitat . — Station 188, September 10, 1874, Arafura Sea;lat. 9° 59' S., long. 139° 42' E.; 
depth, 28 fathoms; bottom, green mud. A single male specimen. 
Remarks. — Notwithstanding the fact that it has five teeth instead of six on the 
dactylus of the raptorial claw, and the very slight development of the longitudinal carinse 
on the hind body, this species bears such a very close general resemblance to the well 
known Squilla nepa, that I was at first inclined to regard it as a smooth specimen of this 
species, with an accidental variation in the number of teeth on the dactylus, and the more 
especially as Squilla nepa is known to occur in the region where the specimen was 
obtained. More careful examination, however, reveals so many minute points of difference 
in all parts of the body that I think there can be no doubt of its distinctness. The 
following, which are the most conspicuous differences, will serve to distinguish it with 
readiness from the latter species. Squilla nepa has six and Squilla quinquedentata five 
spines, including the terminal one, on the dactylus of the raptorial claw. The carinse on 
the anterior edge of the third joint or carpus of the raptorial claw of Squilla nepa is 
irregularly dentated, while it is entire and smooth in Squilla quinquedentata. The 
rostrum of Squilla nepa narrows slightly towards the tip, while that of Squilla quinque- 
dentata is more nearly rectangular. The longitudinal cardiac sutures on the posterior 
portion of the carapace are divergent posteriorly in Squilla nepa, and convergent in 
Squilla quinquedentata. The submedian carinse of the fifth abdominal somite are 
parallel in Squilla nepa, and divergent posteriorly in Squilla quinquedentata. 
Squilla leptosquilla, n. sp. (PI. I. figs. 1, 2). 
Diagnosis. — Ocular segment in front of rostrum. Eyes broad and sub-tri- 
angular. Exposed segments of hind body with submedian carinse. Dactylus of raptorial 
claw with four spines, including the terminal one. Antennulary somite very long, 
reaching to tip of rostrum on middle line, and with its antero-lateral angles prolonged 
forwards into acute spines. First thoracic somite partially exposed dorsally. Lateral 
margins of second, third, and fourth thoracic somites acute. Telson with a long slender 
median spine on dorsal surface, and three pairs of marginal spines, of which the second or 
intermediate pair are much the longest, and the external pair shorter than the submedians, 
and blunt, while the others are acute. First antennae very long. 
General Description. — Eostrum nearly twice as long as wide, subtriangular, with a 
rounded anterior end. Width of carapace between antero-lateral angles about T ® ¥ of its 
greatest width, which is equal to about two-thirds of its length. The length of the 
carapace is T 2 0 o 0 9 0 of the total length of the body, and its antero-lateral angles are produced 
forwards as long acute spines, while the postero-lateral angles are prominent and broadly 
rounded. The gastric area of the carapace is convex and elevated, with an obscure 
