in the Ifuseum of the Smithsonian Institution. 95 



armed above and below ; the fingers are less than half as long as the 

 palm, and gaping ; and the dactylus bears a strong truncated tooth 

 at the middle. In the ambulatory feet the meros-joint is armed 

 with seven to ten spines along the upper edge, and two or three be- 

 low near the extremity; the carpus is slightly taberculatcd, and the 

 penult joint unarmed. 



The adult male specimens before me are entirely naked, but young 

 and female specimens are frequently pubescent. Possibly the adult 

 males may have been accidentally denuded. 



Dimensions of an adult male : Length of carapax, 0.G75 ; breadth, 

 0.57 inch. 



It was found at Cape St. Lucas by Mr. John Xantiis, and 

 there are specimens in the Mnseum of Comparative Zooh)o-v 

 taken at Acapulco by Alexander Agassiz, Esq. 



IlA'a'ljsiielBji iBiiBaida, nov. sjx 



The foUowiug description is that of a female : Bod}' and feet 

 pubescent. Carapax convex, with the regions more protuberant than 

 in the other two species. There are indications of tubercles on the 

 upper sui'face, distributed as in II. cmn^ytacantha, but they are faint 

 protuberances rather tlian tubercles, except the two on the intestinal 

 region, which are small but distinctly prominent. There is a minute 

 sharp spine at the anterior end of the branchial region and one on the 

 hepatic region. On the antero-lateral margin there are no distinct 

 spines, but the rounded surface is covei-ed with minute, sharp tubercles. 

 On the jtostero-lateral margin there are about ten minute spines, the 

 anterior one largest. The horns of the rostruni are small, acute, and 

 placed close together ; they form rather less than half the length of 

 the rostrum. Basal -joint of the antennae short and broad, with a 

 sharp projection at the insertion of the movable pai-t of the antennas 

 not seen in II. camptacantlia / antero-exterior spine straight, acute 

 and pointing obliquely outward; the other spines shorter than in the 

 allied species. In the chelipeds the meros-joint is armed above with 

 eight acute spines ; carpus with one minute spine above and a slight 

 crest on the outer side ; hand unarmed ; fingers little gai>ing ; 

 JULY, 1871. 7 Ann. Lyo. Nat. Hist., Vol. X. 



