KEPOJiT ON ICHTHYOLOGY. 403 



The radial tbruuila is as follows: 



1). Ylll. 17; A. i;5; P. If); V. I. 4. 



The lateral line, from the scapular bones to the end of the second (h)rsal hn, is wx'll 

 marked; it is then deflected and very obscure. 



The color is grayish anteriorly and brownish j)osteriorly. It is covered with black 

 spots, which, on the head and antei-ioi- jKtrtion of the body, are very small and nuiiier- 

 oiis, but posteriorly are larg-er, confluent, and nuich fewer. The doi-sal, caudal, and 

 pectoral fins are quite thickly spotted on the rays; the rays of the anal have also a 

 few spots. The ventrals are nearly immacidate. 



This species is perhaps almost tlie only smooth American Uraneldid wliicli can 



be at once readily distinguished. A single specimen was oljtaincd liy Ih-. (George 



Snckley, in the summer of 1859, between Bridger's Pass and Fort Bridger. It is 



four inches in length. 



rOTAMOCOTTUS CAROLlNiE, GiLL. 



By its general form, this species belongs to the group of which the I'utdiuovottus 

 JRichardsonil is the type, and is nearly allied to that species. 



The body is elongated, slender, and compressed. The head firms twenty-eight 

 luxndredths of the total length, and the caudal eighteen hundredths. The trunk is 

 anteriorly subcylindrical, and its height equals the length of the caudal fin. The 

 thickness at the base of the pectorals is as great or slightly greater than tlie height. 

 From the region of greatest height, the body regidarly declines to the caiulal peduncle, 

 whose height equals a third of the greatest. The breadth declines still more rajjitUy; 

 at the anus, it is equal to little more than half of that at the base of the pectorals, or to 

 a tenth of the total length. 



The head is oval and depressed above. From the snout to the membranous oper- 

 cular mai-gin, it forms twenty-eight hundredths of the total length; its l)readth is about 

 a sixth less than the length. The profile, from the dorsal fin to the snout, is scarcely 

 convex. 



The mouth is large; the jaws arched and receding; the distance between tlie 

 extremities of the maxillaries exceeds a sixth of the entire length, and nearly equals 

 the length of the caudal fin. The maxillaries terminate under tlie posterioi- maiiiin of 

 the pupil. The n])per jaw extends beyond the lower. 



The jaws are armed with acute, curved, approximate teetli; the l)and on the inter- 

 maxillaries is alnuist entire, and extends with little diminution of width to the exti-em- 

 ities of those bones. The band (Ui tlu3 lower jaw is separated by a symphysial inter- 

 val; it diminishes in width to the corners of the mouth. The vomerine and palatine 

 bands are well develojied, and about as large as that of the lower jaw. 



The eyes are moderate, tlu; longitudinal diameter of the orl)it e(puiling a sixth of 

 the head's greatest length. The distance between the center of the pupil and the snout 

 equals a tenth of the entire length. The interorbital'space is scarcely as great as the 

 diameter of the orbit. 



The preopercular sj)ine is large, and curved upward; tiie two inferior arc tul)er- 

 ciilar, the last one smallest. The subopercular spine is acute, and points obliquely 

 forward and downward. 



