282 CRUSTACEA. 



superno ad medium insitd, secundd in lined paralleld externd, tertid 

 juxta basin]. 



Carapax much convex, smooth and shining, median region not crossed 

 by any raised lines, front somewhat arcuate, prseorbital lobe long 

 and very low with a straight and not arcuate outline, antero-lateral 

 margin five-toothed, teeth acute, fourth minute. First joint of 

 outer antennae very long, crest long and entire. Anterior feet short, 

 hand shining, not costate on outer surface, above with three short 

 spines one at middle of upper edge, one on a parallel line exterior 

 to this, and one near base. 



Plate 17, fig. 6 a, male, enlarged two diameters; b, hand, ibid.; c, 

 outer maxilliped ; d, summit of inner branch of first maxillipeds. 



Paumotu Archipelago and Sandwich Islands. 



Length of carapax, seven and a half lines ; breadth, one inch ; ratio 

 of length to breadth, 1 : 1'33. The general outline is much like that 

 of the Poissanii of Audouin (Egypte, Crust., de M. Savigny, pi. 4, 

 'f. 3 and 4), and also like the figure of the arcuatus of De Haan 

 (Fauna Japon., Crust., PL 13, fig. 1) ; but, unlike the former, it has 

 only two short spines on the upper surface of the hand beside the 

 basal one, and neither of these is at the apex of the hand. Unlike 

 the latter, the hand is not punctate above, the prseorbital tooth or 

 lobe is longer and lower, and not arcuate in outline ; the fourth lateral 

 tooth is much smaller. At the apex of the hand there is a right 

 angle in the margin, but no spine. The Thalamita sima also resembles 

 this in outline, but the hand is strong costate without, and provided 

 also with an apical spine. The smooth hand and carapax, and its 

 unusual convexity, are prominent peculiarities; also the entire margin 

 of the crest on the base of the outer antennae. 



2. From mutiilobatus. 



THALAMITA CRENATA (La.tr.} Edw. 



Plate 17, fig. 7 a, under view, showing crest of the base of outer 

 antennae ; b, summit of inner branch of first maxillipeds. 



