41 



ovate above ; it forms, from the snout to the membranous margin of 

 the operculum, a third of the entire length. The snout is broadly- 

 rounded before. The mouth is large, the distance between the ex- 

 tremities of the maxillaries equalling the length of the caudal fin. The 

 eyes are nearly central and of the usual size ; the width of the frontal 

 bones between them equals one of their diameters. The lateral line 

 from the scapular bones to the end of the second dorsal fin is well 

 marked ; it is thence deflected and very obscure. 



D. 8-17 ; A. 13 ; P. 15 ; Y. 1-4. 



The color before is grayish, and behind brownish ; there are numer- 

 ous black spots, which on the head and anterior portion of the body 

 are very small and abundant, but behind are larger, confluent, and 

 much fewer. The rays of the dorsal, caudal, and pectoral fins are 

 quite thickly spotted ; the rays of the anal have also some spots, but 

 the ventrals are nearly immaculate. 



This species is one of the most easily distinguished of the Ameri- 

 can Cotti ; one specimen was obtained by Dr. George Suckley, in the 

 summer of 1859, between Bridger's Pass and Fort Bridger ; it is four 

 inches in length. 



POTAMOCOTTUS CaROLIXJE Gill. 



This species is most nearly alHed to the Cottus or Potamocottus 

 RicTiardsonii The head forms twenty-eight hundredths (28-100) of 

 the total length above ; it is oval and depressed, and its breadth is 

 about a sixth less than the length. The mouth is large, and the dis- 

 tance between the ends of the maxillary bones exceeds a sixth of the 

 total length, and nearly equals the length of the caudal fin. The 

 eyes are moderate ; the longitudinal diameter of the orbit equalling 

 a sixth of the head's greatest length. The distance between the 

 centre of the pupil and the snout equals a tenth of the entire length. 

 The interorbital space scarcely equals the diameter of the orbit. 

 The caudal fin forms eighteen hundredths (18-100) of the total 

 length. The lateral line is continued in an almost straight direction 

 to the base of the caudal fin, the deflection under the posterior part 

 of the dorsal fin being slight ; the cutaneous keel, in which the pores 

 open, is most developed behind. 



D. 8-17; A. 121; P. 16; V. 1-4. 



The color differs little from that of the allied species. There are 

 four rather darker transverse dorsal bands ; one under the first dorsal 

 fin, one under the anterior and another under the posterior parts of 

 the second dorsal, and a fourth at the base of the caudal fin. The 

 spinous dorsal is punctulated with darker, especially between the 

 anterior rays. The other fins are hyaline. The head is darkest 

 above. 



The Potamocottus Carolines is one of the largest species of the 

 genus, and even exceeds the Potamocottus punctulatus in size. It is 



