182 Bulletin Vanderhilt Marine Museum, Vol. V 



Material examined : One large male from Papeete, Tahiti, Society 

 Islands, August 16, 1931. A smaller female taken on Venus Point 

 Reef, Tahiti, Society Islands, August 15, 1931, both collected by the 

 ''Alva." 



Technical description : Carapace oval, nearly circular, thin, flat- 

 tish, disk-like, about 2 mm. longer than wide ; regions imperfectly de- 

 lineated; the dorsal surface finely punctate and with a velvety fine 

 coating of minute setae ; a few, widely scattered, low, rounded, tuber- 

 cles are present ; some of these form an incomplete circle around the 

 central portion of the carapace; others form an irregular line along 

 the posterior margin of the carapace. The front, antennular and pre- 

 orbital angles and epistome all are deeply sharply spinose. The frontal 

 region between the antennae is narrow, approximately twice as long as 

 wide proximally, armed with three or four forward-directed spinules 

 proximally along each margin, followed by a pair of prominent acute 

 forward-directed spines, one on each side, midway the lateral margin, 

 beyond which the rostrum narrows and is deflected, terminating in a 

 pair of acute, forward and upward-pointing spines, separated by a 

 V-shaped space. The preorbital angles also terminate in a sharp up- 

 curved spine, equal to and in line with the distal rostral spines. Be- 

 hind this are a pair of smaller acute, upward-pointing spines, one on 

 the inner margin and the other on the outer or preorbital margin, 

 both in line with the subdistal spine of the rostrum ; a third small spine 

 occurs behind the second outer spine on the preorbital margin. The 

 outer half of the superior orbital margin is serrate, with seven or eight 

 acute spines ; the postorbital angle is a larger, acute tooth ; behind it on 

 the anterolateral margin there are three subequally spaced, acute 

 teeth, decreasing slightly in size from the first to third. The postlat- 

 eral and posterior margins are slightly carinate. The epistome is 

 armed with five acute spines, the outermost pair being slightly larger 

 than the median spine, while the submedian pair are subequal to the 

 median spine; the outermost pair are visible dorsally; the median 

 spine would also be except that it lies beneath the rostral spines. The 

 side walls of the carapace and sternal plastron are smooth. The male 

 belt is triangular with rounded tip. The first and second articles are 

 narrow, hinge-like, the third, fourth and fifth articles are completely 

 fused into one long article ; the sixth article is nearly as long as wide ; 

 the seventh segment is broadly rounded distally. The female belt is 

 widely oval, smooth, nearly subcircular, with the first and second seg- 

 ments short, hinge-like, the third, fourth and fifth segments completely 



