in the Museum of the Smithsonian Institution. 115 



l)\it generally there are seven or eight teeth behind the obtuse tubercii- 

 hited space near the orbit, or rather behind the point where the 

 transverse subhepatic ridge joins the margin; the teeth increase in 

 size posteriorly, and each one is composed of two or three denticles, 

 the median one being largest where there are three. The postero- 

 lateral margin is thickened, as if double ; it is irregularly tubercu- 

 lated, and bears two strong triangular teeth, one next the lateral tooth 

 of the carapax and the other next the posterior extremity. The 

 posterior extremity of the carapax is narrow, with two thickened, 

 tuberculated margins placed one above the other. Beneath, the sur- 

 face of the body is rough with pits and tubercles both anteriorly and 

 posteriorly; but the subbranchial region is smooth. Chelipeds angu- 

 lar ; meros smooth below, a.nd having a transverse, creniilated, lami- 

 niform crest at the superior extremity, following the upper j^art of 

 the base of the carpus; supero-exterior surface of the carpus nearly 

 smooth ; superior crest of the hand with three equal teeth ; outer 

 surface of hand with five longitudinal ridges, the three upper ridges 

 formed of large, the two lower ones of small tubercles. Ambulatory 

 feet nearly as in 0. tuberosa, but with the crests less prominent, that 

 of the meros-joint not pitted, but faintly denticulated and sparsely 

 hairy. 



Color yellowish, with spots of red and white resembling patches of 

 lichen. 



Dimensions of a male : Length of carapax, 0.70; greatest breadth, 

 at the antepenult antero-lateral tooth, 0.83 inch. 



There are several specimens of this species in the Smithso- 

 nian Collection, which were taken at Panama by Capt. J. M. 

 Dow, and at Manzanillo by John Xantus, Esq. 



liithadfia poiitifera, nov. sp. 



The following description is that of an adult female, the only spe- 

 cimen I have seen. The carapax is rather broader and less convex 

 than in other species of the gemis, and has an angular outline, with 

 an aspect somewhat like that of a Nursia. The sides project con- 

 siderably over the bases of the feet. The entire upper surface is 



