372 



CRUSTACEA. 



Plate 23, fig. 10 a, animal, natural size; b, front view of front, en- 

 larged four and a half diameters; c, outer maxilliped, enlarged four 

 diameters; d, abdomen and sternum, natural size. 



New South Wales. — Received from the Rev. Mr. Wilton, of New- 

 castle, N. S. W. 



Length of carapax of a male, nine lines ; breadth, nine lines, but be- 

 tween tips of lateral teeth, nine and two-thirds lines; length of hand, five 

 lines; height, three lines; length of hand along upper margin to finger, 

 one and three-fourths lines. The crest on the beak runs nearly 

 parallel with the front margin either side of the medial depression; it 

 is minutely crenulate as seen with a lens. The antennaiy incision is 

 more oblique than in the other Plagusia^, and not as deep. The 

 carpus has a flattened surface and an acute point within, with the 

 upper edge of this flattened surface nearly a right angle. The outer 

 antennas are placed quite obliquely, and the first joint has the outer 

 apex much prolonged, the prolongation being equal in length to the 

 second joint. The fingers are nearly entire on the inner edge. The 

 form of the third joint of the outer maxillipeds is a little oblong, 

 although scarcely narrower than the apex of the second joint, while in 

 the other Plagusias it is transverse. The palpus of these maxillipeds 

 has a flagellum, and the basal part is as long as the second joint of 

 these organs. 



Genus ACANTHOPUS, Dc Uaan. 



The narrow oblong form of the third joint of the outer maxillipeds 

 (much narrower than apex of second joint), together with the absence 

 of a transverse plate from the inner branch of the first maxillipeds, 

 and the very short palpus appended to the outer maxillipeds, it being 

 a simple styliform joint, afforded De Haan sufficient ground for separa- 

 ting from the other Plagusiaa the species included in this genus. 



ACANTHOPUS PLANISSIMUS (Hcrhdf). 



Madeira; Raraka, in the Paumotu Archipelago ; Tahiti, Societv 



