32 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM 



a conspicuous cutaneous fold below and a smaller but evident one 

 above. Upper jaw considerably curved, with a sligbt convex protuber- 

 ance in front, which fits into a slight emargination in the lower jaw, 

 which is convex, its outlines corresponding to the curves of the upper 

 jaw. Bands of teeth wider in front than laterally. Inside of mouth 

 behind the lower jaw with three fleshy processes. Teeth about f^; 

 about 8 in a cross-series in the upper jaw and 10 in the lower. 



Color light brown, somewhat marbled with darker, but without dis- 

 tinct spots ; tail blackish ; belly white. 



Skin everywhere perfectly smooth in all the specimens seen. 



Measurements of two specimens. 



No. 1. No. 2. 



Length of disk (in inches) 8.75 8.50 



Length of tail (in inches) 12.25 12.40 



Breadth of dislc Percentage of length of disk 1. 01 1. 10 



Distance from disk to dorsal fold " 45 ..53 



Length of dorsal fold " 135 .155 



Height of dorsal fold " 0175 .019 



Distance from root of tail to anal fold. " 38 .375 



Length of anal fold *' 30 .365 



Height of anal fold " . 02>5 .0225 



Length of suont from eye . = - " 21 .18 



luterorbital width " 13 .115 



Snout to scapular ridge " 32 .335 



Distance between nostrils " 155 .15 



Width of mouth " 11 .11 



Length of branchial area " 195 .18 



Widthof branchial area (in front) — " 32 .31 



Mouth to vent " 70 .70 



Length of caudal spine " (lost) .335 



Distance of spine from disk " 35 .325 



This species is known to us from four female specimens taken in San 

 Diego Bay. These range in length from 18 to 24 inches, and are there- 

 fore but partially grown. Several other specimens, some of them larger, 

 have been seen in a pile of refuse fish throw^n away by the Chinese fish- 

 ermen. These were, however, too far gone for preservation or descrip- 

 tion. 



52. Platyrhina exasperata sp. nov. 



Disk rhombic, about as broad as long, the snout prominent, but 

 bluntish at the tip, the angle made by the anterior margins of the pec- 

 torals rather less than a right angle, but the snout itself rounded at the 

 tip. Anterior margin of pectorals nearly straight. 



Eyes rather large ; nasal ridges well separated, little converging, not 

 meeting anteriorly. Mouth rather narrow, slightly convex forward. 

 Teeth about |f . Nostrils with a large anterior flap, which projects back- 

 wards and covers a narrower posterior flap. 



Ventral fins separate, entire, their outer margin slightly convex. 



Tail depressed, with a broad lateral fold ; dorsal fins comparatively 



