ISOPONDYLI— SALMONIDAE— SALMO PLEURITICUS. 693 



Of these specimens eight or ten individuals are from Provo ; six or 



eight from Panquitch. 



SALMO SPILURUS, Cope. 



Salmo spilurus, Cope, U. S. Geo]. Surv. Montana, &c, 1871, 470. 



This fish was only observed in the Brazos River, one of the principal 

 head tributaries of the Chama. Twenty-three specimens were examined, 

 which all agree in possessing larger scales, a lighter color, and a larger size 

 than the S. pleuriticus, which lives in the same region. This trout is the 

 finest game and food fish of New Mexico, as the members of our party had 

 good opportunity of ascertaining. It has so far only been found in the head- 

 waters of the Rio Grande, near the mountain ranges, and perhaps may 

 prove to be a large and well marked race of the more widely distributed S. 

 pleuriticus. On six specimens, the following numbers of scales were counted 

 above and below the lateral line: (1) 5; (2) 3 2; (3) 3 i; (4) ±L; (5) ^ (6) 



?i. The cranium is not keeled on the middle line. The color is a very 



38 J 



light yellowish-brown, marked with small spots, which are- composed of 

 decussating lines. There are but few of them in advance of the anal fins, 

 and none (except in one) in front of the ventrals. A red band on each side 

 of the chin. 



SALMO PLEURITICUS, Cope. 



Salmo pleuriticus, Cope, U. S. Geol. Surv. Wyoming, 1870, 433.— Id., U. S. Geol. Surv. 

 Montana, 1871, 471.— Id., Proc. Am. Phil. Soc. Phila., 1874, 132.— Id., Rep. 

 Plagop. & Ichthy. Utah, 1874, 6. 



Description. — A stout species with obtusely descending muzzle ; large 

 subcircular eye, which enters head four times. Cranial keel well marked, 

 its elevation being greater between orbits than on posterior part of frontal 

 bones. Interorbital width 1.33 times long diameter of the interpalpebral 

 opening of the eye. Dorsal fin nearer the origin of the marginal rays of 

 the caudal than to the end of the muzzle, but is midway between the latter 

 and the termination of the scales on the sides of the fins. 



Radii: Br. XI; D. 2, 11-12 and 13 ; A. II. 11. Scales from 40 to 45 

 below first dorsal ray ■ to lateral line. Maxillary bone extends a little 

 beyond posterior rim of orbit; is not expanded. This species is well spotted, 



