PLECTOSPONDYLI CYPRINIDAE PANTOSTEUS VIRESCENS. 675 



which the length of the head enters 5.3 times; orbit small, 4.6 times in 

 length of head, twice in interorbital width, and 1.75 times in muzzle ; the 

 latter projecting a little beyond month, not depressed, but narrowed viewed 

 from above. Labial folds well developed, tubercular, the anterior rather 

 narrow, the posterior deeply incised. Commissure with acute cartilaginous 



14 



edge, regularly convex forward. Scales, is. 



14 



Total length, O m .107 ; -length to basis of caudal, O ra .0933 ; length to basis 

 of ventral, O m .052 ; length to basis of dorsal, (T.047 ; length of head, O m .0205 ; 

 width of muzzle at mouth, O m .075 ; width of head at pterotics, O m .011. 



Color light-brown, with numerous dusky spots and clouds ; a narrow 

 abdominal band light ; fins and chin (?) red. 



Two specimens of this species were obtained by the expedition of 1873 

 in the Zufii River, a tributary of the Colorado. In 1874, we found it very 

 abundant in the tributaries of the Rio Grande as far as we explored it, i. e., 

 from Fort Garland, Colo., to Santa Ft'. It is the prevalent Catostomoid 

 of that river basin, and is everywhere associated with the Salmo pleuriticus 

 and Gila pandora, &c. It imitates the coloration of the former in having a 

 broad crimson band along the middle of each side in spring and summer. 

 Below this there is frequently a broad blackish band. The scales below the 

 lateral line vary from 11 to 14, and those on the line from 80 to 87. The 

 dorsal fin rarely has 10 rays. 



The species was dedicated to Dr. H. C. Yarrow in recognition of his 

 important services to zoological science. 



PANTOSTEUS VIRESCENS, Cope, sp. nov. 



An elongate fish, with short, wide head and compressed body ; the 

 caudal peduncle rather contracted. Muzzle obtuse, projecting but little 



