182 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY III. 



ANALYSIS OF SPECIES OF PANTOSTEUS. 



* Scales very small, 100 to 105 in the lateral line; 18 above and 16 below, in a cross- 

 series : . body elongate, compressed, the caudal peduncle contracted : head short, 

 wide, 5 in length : muzzle obtuse, little projecting; upper lip wide; lower lip 

 full, emarginate ; jaws with well developed cartilaginous sheaths : scales much 

 reduced in size forwards : dorsal rays 10 ; ventral 9 : color olive ; lower surface 

 yellow VIRESCEXS, 33. 



** Scales small, 80 to 85 in the course of the lateral line. 



t Scales very much reduced and crowded anteriorly : upper lip full, pendent; cartila- 

 ginous sheaths on jaws well developed, the commissure transverse and ab- 

 ruptly angulate at the corners of the mouth. 



a. Body extremely elongate, the depth 5| to 7 in length : head 4f in length, short , 

 and wide, with depressed and expanded muzzle, which considerably overhangs 

 the mouth : isthmus very wide : dorsal rays 11 ; ventral rays 9 : scales 15-86-12 : 



belly and lower fins yellowish, probably red in life PLATYRHYNCHUS, 39. 



aa. Body moderately elongate, the depth 4 to 5 in the length : head rather short, 

 4f in length, not specially broadened; muzzle not greatly overhanging the 

 mouth : dorsal rays 9 (raiely 10) ; ventral rays 10 (rarely 9) : scales 11 to 14-83 

 to 87-13 to 15 : light brown above, with dusky spots and clouds ; males with 



% 



the chin and fins red, and a crimson lateral band GENEROSUS, 40. 



tt Scales subequal over the body, not much reduced forwards : upper lip rather nar- 

 row, cot pendent ; cartilaginous sheath on jaws obsolete (?). 

 I). Body comparatively stout, the caudal peduncle short and thick, the back some- 

 what arched, the depth 4-- to 5 in length : head short and wide, ilattish above, 

 4$ to 5 in length : scales 14-84-15 : dorsal rays 9 to 11 ; ventral rays 10 : black- 

 ish above, with one or two dark lateral shades ...PLEBEIUS, 41. 



38. PANTOSTEUS VIBESOENS Cope. 



Green Sucker. 

 1876Pantostius virescens (COPE) COPE & YARROW, Wheeler's Expl. W. 100th Mer. v, 



Zool. 675. 

 Pavtosteus virescens JORDAN & COPELAND, Check List, 156, 1876. 



HABITAT. Arkansas River in Colorado. 



Only a single specimen of this species is known, collected by Mr. C. 

 E. Aiken at Pueblo, Colo. The small size of its scales indicates its 

 distinctness from the other species of Pantosteus. The greenness of 

 coloration of the typical specimen is 'probably due to its having been 

 kept in a copper tank. 



Specimens in United States National Museum. 



