CRUSTACEA. 24l 



ambulatory legs. The eye-peduncles are very short and thick, with 

 very large cornese ; the antennules are transverse ; the basal joint 

 of the antennae is slender, and although longer than the two fol- 

 lowing joints, does not reach to the subl'rontal process ; the ischium- 

 joint of the outer maxillipcdcs is rather short and broad, but longer 

 than the next joint and longitudinally sulcated ; the merus is 

 quadrate, the slender exognath reaches to the distal end of the 

 merus. The chelipcdes are subequal and of moderate size, and, as 

 already stated, pubescent ; the merus or arm is trigonous and has a 

 tooth near the distal cud of its upper margin ; the carpus is armed 

 with a strong spine on its inner surface ; palm somewhat shorter 

 than the fingers, the margins not cristatcd, the fingers regularly 

 denticulated and meeting along their inner margins and acute at 

 their apices, but without a tuft of hair at base. The ambulatory 

 legs are slender, with the joints somewhat compressed and scantily 

 pubescent ; the margins of the penultimate and terminal joints of the 

 last pair of legs are fringed with long hairs, but the terminal joint 

 of the last pair of legs is styliform and not dilated. The bases of 

 the male verges lie in wide open canaliculi of the sternum, and these 

 organs (in the single specimen examined, which is probably not 

 adult) are nearly straight. Colour (in spirit) whitish. Length of 

 the carapace of the male 3g lines (nearly 8 millim.), breadth 4| lines 

 (nearly ] millim.) ; length of chelipede when fully extended nearly 

 | inch (12 millim.), of second ambulatory leg about 7| lines 

 (16 millim.). 



Two specimens, one a male and the other sterile, were collected 

 in the Arafura Sea, 32-36 fms. (Xo. 160). 



Haswell's types were from Holborn Island, Port Denison (20 fms.). 

 As, in his brief description, he does not mention the pubescence of 

 the carapace, and as his specimens differ in coloration, it is pos- 

 sible that ours are distinct ; and if so, I would propose to designate 

 them P. Jiasivelli. 



Carcinoplax vestitus*, as figured by De Haan, differs in its some- 

 what narrower front, in the shorter, less prominent third antero-lateral 

 spine, more quadrate carapace, less compressed chelipedcs, and in the 

 absence of long cilia from the terminal joint of the dactyli of the 

 fifth ambulatory legs. 



The distinctions between the genera Carcinoplax, Eucrate, and 

 Pilumnoplax of Stimpson f are very slight, and a revision of the 

 group is urgently needed. If, as is probable, all three genera should 

 have to be united, the designation Pseudorhombila will, I think, tako 

 precedence, since De Haan's name Eucrate differs by a letter only 

 from the earlier name Eucratea, and Curtonotus had previously been 

 used in the Coleoptera. 



* Cancer (Curtonotus) vestitus, De Haan, in Siebold, Fauna Japonica, Crust, 

 p. 51, pi. v. fig. 3(1835). 

 t Proc. Acad. Nat. Sci. Philad. p. 93 (1858). 



B 



