252 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



upper parts of the body, but they are not e^^euly distributed, and in 

 most regions they are placed quite wide apart. They are hirgest and 

 most numerous on the nasal ridges, interorbital space, middle region of 

 back and tail, and anterior part of pectorals. On the base and edges of 

 the jjectorals and on the ventrals the prickles are few and small. On 

 the middle portion of the pectorals they are rather numerous. Under- 

 side of disk everywhere prickly except along the edges of the fins; the 

 j)rickles largest under the snout. 



Male not seen, probably differing, as in the other species, in the sparser 

 prickles above, in the absence of a lateral caudal series, and in the pres- 

 ence of stouter prickles on the anterior part of the pectorals and of claw- 

 l\^e spines on the posterior part. Mouth somewhat arched. Teeth 

 about -\%. i^asal flap rather less than half the width of the mouth. 



Coloration essentially as in Eaia hinoculata. Light brown above, 

 vaguely mottled with paler; the usual dark ring at the base of the pec- 

 torals most distinct in fresh examples, and j)robably in the young. 



This species is known to us from three examples. Adult females, 26 to 

 29 inches in length. One from Monterey Bay and two from San Fran- 

 cisco Bay. The one from Monterey was referred to in our description 

 of Raid stellulata as a long-nosed form or variety of Eaia hinoculata. 



Rata rhina, is related to Raia cooperi and Rata hinoculata. From the 

 latter it differs in the much sharper and longer snout, in the less coQcave 

 interorbital space, and in the much greater roughness of the body, the 

 small prickles, even in the female of R. hinoculata, being confined to the 

 snout, interocular space, and a portion of the median region of the back 

 and the tail, the fins being [)erfectly smooth. The male has the usual 

 patches on the pectoral tins, and the back almost or quite smooth. 



From Raia cooperi, Raia rliina differs in the much smaller size in length, 

 the adult of Raia cooper i reaching at least a length of more than six feet. 

 It also differs in form, color, interorbital width, armature, «&c., as will 

 ajjpear from the following descrix)tion of a young male example of Raia 

 cooperi, 27^ inches in length, from San Francisco. 



Disk broad, its widest part much heliind the middle, the pectoral angle 

 rather sharp, and the posterior edge very little convex. The anterior 

 margm of the pectoral is at first slightly convex, then concave, then, op- 

 posite the eyes, again very slightly convex, then again slightly concave; 

 the snout itself not very sharp, although long. 



Interorbital space very broad and almost fiat (deeply concave in R. 

 hinoculata), only slightly depressed in the middle, the nasal ridges well 

 separated for usually two-thirds their length. Supraocular ridge not at 

 all elevated. Eyes quite small, shorter than the spiracles. 



Ventral tiujinot deeply emarginate (becoming more deei)ly emarginate 

 in the adult). Caspers, in this example (which, although larger than 

 the adults of the other species, is evidently immature), very small, 

 scarcely exserted beyond the ventral edge. Claw-like pectoral spines 

 not yet developed. Caudal fin wanting. Dorsal fins moderate, not far 



