282 COLLECTIONS FROM MELANESIA. 



Seven specimens were collected at Port Darwin at 12 fms (in- 

 cluding both sexes) ; two or three are females with ova. In the 

 last collection from H.M.S. ' Alert ' specimens from Singapore 

 are apparently not specifically distinguishable, although presenting 

 some slight distinctions. 



From Gebiopsis nitidus, A. M.-Edwards *, from the Cape Verds 

 (the type of the genus), this species is distinguished by the somewhat 

 different form of the rostrum, the existence of a spine on the 

 carpus of the chelipedes, the much shorter antennulary and antennal 

 peduncles, etc. 



A male from Freraantle, S.W. Australia (Dr. J. S. Boiverbank), 

 differs in the form of the rostrum, which is anteriorly deflexed ; its 

 margins armed with ten spines in front of the first of the denticules 

 of the sides of the head ; of these, four (of which two are longer) are 

 arranged in a semicircle in front, and three, posterior to them, on 

 each side. I would propose to designate this, if specifically distinct, 

 G. bowerbciitLii. 



The genus Gebiopsis scarcely differs from Gebia, except in the 

 greater development of the lower finger of the chelipedes (which 

 thus are perfectly chelate), and is probably to be regarded as a sub- 

 genus. 



J3. Axius plectrorhynchus, Strdkl. 



I am somewhat uncertain of the identity of the specimen in the 

 ' Alert ' collection with Strahl's type from Luzon, and therefore 

 subjoin the following description : — 



The carapace and postabdomen are somewhat membranaceous in 

 texture, as in most species of the genus. The cephalothorax is ver- 

 tically deep and laterally compressed; the carapace is smooth, 

 without spines, and has the cervical suture distinctly marked. The 

 rostrum is prominent and narrow, concave above between the eyes ; 

 it is produced somewhat behind them, and is armed on the lateral 

 margins with five or six teeth ; at the base of the rostrum, in the 

 median dorsal line, the carapace rises into an abrupt prominence ; 

 both the gastric and cardiac regions are distinctly defined. The 

 postabdominal segments are smooth, the first very small, the rest 

 nearly of equal length ; the lateral margins of the second to sixth 

 segments are nearly straight, entire, and are not produced into spines 

 at either the antero-lateral or postero-lateral angles ; the terminal 

 segment is quadrate, very little broader than long, a little broader 

 in its proximal than in its distal half, and has its posterior margin 

 straight. The eyes are of moderate length and thickness, and have 

 distinct black corneas ; the antennules are of moderate length, their 

 antepenultimate joints longer than the two following, which are 

 subequal ; the two flagella are of equal thickness, with naked joints. 

 The antennas are shorter than the animal, the antepenultimate joint 

 of the peduncle shorter than the following, and armed beneath with 

 a small spinule ; the penultimate joint longer than the last joint ; the 



* Nouv. Arehiv. Mus. Hist. Nat. iv. p. 63, pi. xviii. figs. 4-7 (1868). 



