REPORT ON THE CRUSTACEA MACRURA. 255 



The third pair of pereiopoda is longer than the preceding, it does not carry any tooth, 

 but the basis supports an ecphysis, and the coxa carries a single-branched mastigobranchia, 

 which is pedunculated, broad at the base, and tapering. The oviducts are attached to the 

 coxal joints in the form of a projecting tubercle directed obliquely inwards and posteriorly. 



The fourth aud fifth pairs of pereiopoda are long, tolerably robust, and terminate in 

 long, flattened, lanceolate dactyli ; each carrying a basecphysis but no mastigobranchia. 



On the ventral surface (fig. 1'") between the second pair of pereiopoda, two long 

 spine-like teeth project, one on each side of the median line, and between the last two 

 pairs lies a cordiform thelycum, flat in the middle, elevated, and surrounded by a margin 

 fringed with hairs. 



The anterior pair of pleopoda (p) has the outer branch long, flattened and tapering, 

 the inner minute and rudimentary, and situated near the inner distal angle of the basisal 

 joint. The four following pairs are subequally biramose. 



The male differs very little from the female in general aspect. The several parts 

 appear to be a little more pronounced, but the two long and slender teeth, so conspicuous 

 on the ventral surface in the female, are wanting. 



The vas deferens projects from the posterior pair of pereiopoda, and the petasma 

 (fig. 1", p) attached to the first pair of pleopoda springs from near the base of the basisal 

 joint, and is produced into a longitudinally folded leaf-like appendage, intimately 

 linked together in the median line by small cincinnuli. All the other pairs are similar to 

 those in the female ; the sixth pair, which aids in the formation of the rhipidura, is long, 

 narrow, and rounded at the extremity. 



The telson (lz) is as long as the lateral plates, furnished on each side with four spines, 

 and one spine-like tooth, and terminates in a long and slender point. 



Forty-five specimens of this species were taken both with the trawl and the dredge 

 south of New Guinea, and several others at different Stations in the same region, 

 associated in some instances with Polycheles ; and twenty-one were dredged in the narrow 

 channel between the islands on the southern coast of Japan. 



Stimpson records specimens from Japan, at from 4 or 5 to 30 fathoms, on a sandy 

 bottom. 



This species is essentially an inhabitant of shallow water, and as such was found in 

 the channel referred to, where the water is only from 8 to 50 fathoms deep, a depth 

 that corresponds with that of most of the other recorded localities. The great variation 

 in the depth at which two specimens were taken in the same region can only be accounted 

 for by the fact that the deep water comes up close to the southern shores of Japan. I 

 am therefore induced to believe that those obtained from the greater depth of 2675 

 fathoms were caught swimming in mid-water, and carried down previously to their being 

 brought up in the dredge, a supposition that is supported by their soft and somewhat 

 damaged condition. 



