NO. 2047. AMERICAN BRACHYRHYNCH0U8 CRABS— RATHBUN. 121 



Our species resembles Pachygrapsus crassipes Kandall ^ but the 

 carapace is narrower and more convex, the post-frontal lobes lower, 

 the lateral tooth not acute nor prominent, the postero-lateral margins 

 less convergent, dorsal striae finer and more broken, those of the 

 branchial region less extensive, palm without a definite marginal line 

 above, last four segments of the abdomen of the male more regularly 

 triangular. 



Subfamily Vj^E,XJISriI>r.^E;. 

 CYRTOGRAPSUS ALTIMANUS, new species. 

 Plate 4. 



Type-locality. — San Matias Bay, Patagonia; Hassler Expedition. 



Additional locality. — Rio Grande do Sul, Brazil. 



Type.— Male, Cat. No. 6126, M.C.Z. Two male paratypes in U. S. 

 National Museum, Cat. No. 22835. 



Dimensions. — Length of carapace of type male 16.8 mm., width of 

 same, 18.4 mm. 



This species while closely related to C. angulatus Dana,- which 

 inhabits the same region, is much smoother and less ornate so that 

 there is no likelihood of their being confused. 



The carapace is not strongly areolated though the regions are well 

 defined; the gastric region lacks the beaded transverse ridge charac- 

 teristic of the older species. The surface is densely covered with fine 

 depressed granules and somewhat less numerous punctse; it appears 

 almost smooth to the naked eye, while in angulatus the surface 

 is obviously roughened with coarser granules. As to shape, the 

 carapace has no sharp lateral angles, the antero-lateral margins are 

 shorter than in angulatus, and the postero-lateral margins are longer 

 and subparallel to each other. The antero-lateral margins have four 

 teeth, including the orbital tooth, but they are small, .especially the 

 last two, and do not project beyond the marginal line; the intervals 

 between the teeth diminish successively in length. There is no indica- 

 tion of a postero-lateral tooth. 



The front is relatively wider than in angulatus and is feebly emar- 

 ginate at the middle; the orbits are correspondingly smaller. 



The outer maxillipeds have much the same shape in the two 

 species, but in altimanus they are shorter and wider and the gape 

 narrower. 



The palms in the adult male are much higher in our species, espec- 

 ially at the distal end, and the movable finger is strongly dcflexed; 

 the immovable finger is nearly horizontal; there is a triangular space 

 between the fingers for their proximal half only. 



1 Journ. Acad. Nat. Sei. Phila., vol. 8, 1839 (1840), p. 127. 



a Proc. Acad. Nat. Sei. Phila., vol. 5, 1851, p. 250; Crust. U. S. Expl. Exped., vol. 1, 1852, p. 352; atlas, 

 1855, pi. 22, fig. 6o-«. 



