No. 2047. AMERICAN BRACHYRHYNCHOVS CRABS— RATHBUN. 119 



the sternum; the slender, deflexed fingers of the chelae, and the 

 strongly upcurved dactyli of the last pair of legs also separate the 

 genus from Eucratopsis. 



CYRTOPLAX SPINIDENTATA (Benedict). 



Plate 2. 



Eucratoplaz spinidentata Benedict, Johns Hopkins Univ. Circ, vol. 11, 1892, 



p. 77. 

 Eucratopsis spinidentata Rathbun, Bull. U. S. Fish Comm. for 1900, vol. 2, 



1901, p. 11. 



Type-locality.— J Simsiica, . 

 Type.— Cat. No. 17219, U.S.N.M. 

 Distribution. — Jamaica; Porto Rico; Trinidad. 



CHASMOPHORA,! new genus. 



Type of the genus. — ChasTnoplwra macrophtlialma (Rathbun). 



Carapace very broad, subcyhndrical, very convex longitudinally, 

 much less so transversely; antero-lateral margin short, dentate. 

 Fronto-orbital border about four-fifths 

 the width of the carapace. Front sepa- 

 rated from the orbital angle by a fur- 

 row. Eyes stout, filling the orbit; lower 

 margin of orbit with a large outer sinus. 

 Basal joint of antennae not reaching the 

 front, flagellum standing in the orbital 

 hiatus. Buccal cavity widening anteri- 

 orly, entirely filled by the outer maxil- fig- 2.-chasmophoea macrophthal- 



,. , 1- , 1 1 c c -If 1 MA, ANTERIOR ^^EW OF OKBIT OF TYPE 



lipeds ; distal angle ot merus or maxiUipeds female, showing hiatus, in which 

 prominent. Right chehped of mecHum "^^ "^^^ antennal flagellum, x 

 size; left not known. Legs slender. First 



segment of abdomen of female very broad, but not covering the whole 

 width of the sternum; third segment narrower. It is probable that 

 in the male these segments have a similar relation to the sternum. 



Near Euryplax Stimpson,^ in winch the antennal flagellum is 

 widely removed from the orbit by a large process of the basal joint. 



CHASMOPHORA MACROPHTHALMA (Rathbun). 



Eucratopsis macrophthalnia Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 601, 

 pi. 43, figs. 3 and 4. 



Type-locality.— F&n&msi Bay, lat. 7° 56' 00" N.; long. 79° 41' 

 30" W., 51.5 fathoms, green mud, station 2805, U. S. Fisheries 

 steamer Albatross. 



Type.— Cat. No. 21591, U.S.N.M. 



1 Xiaiia, an opening; <fMpi, an orbit. 



2 Ann. Lye. Nat. Hist. N. Y., vol. 7, 1859, p. 60. 



