85. PERCID^E ALVOEDIUS. 501 



Cheeks naked; opercles scaly above only; space before dorsal naked; muzzle 



blunt. 



d. Ventral shields moderate ; colors dull, plain crassus. 



dd. Ventral shields very large, 4 or 5 times the size of the ordinary scales ; colors 



brilliant variatiis. 



aa. Vertebrae less than 40 ; dorsal spines 10 or 11; palatine teeth obsolete ; males with 



the lower fins tuberculate in spring. (Erivosma Jordan.) evides, fasciatus. 



a. Vertebrae more than 40 ; dorsal spines 11 to 15; palatine teeth present. (Alvordius.) 

 6. Cheeks and opercles entirely scaleless ; head very long and large ; lat. 1. 75 to 80. 



781. A. macrocepEialus (Cope) Jor. 



Body elongate. Head long and large ; mouth rather large, maxillary 

 reaching to opposite anterior margin of orbit. Eye shorter than snout, 

 4 in head. Ventral shields twice as large as other scales. Head, neck, 

 aud chest without scales. Color light brown, with a slightly undula- 

 ting whitish band from upper angle of opercle to caudal peduncle ; back 

 with dark quadrate spots ; sides with 9 blackish longitudinal spots, 

 alternating with smaller ones; streaks downward and forward from 

 eye; vertical fins somewhat barred; spinous dorsal with a median 

 blackish band ; head spotted above. Head 3; depth 7. D. XV-13; 

 A. II, 11; scales 11-77-15. L. 3 inches. Ohio Valley; not very common. 



(Etlieosioma macroceplialum Cope, Trans. Am. Philos. Soc. 1866, 401; Jordan, Man. 

 Vert. ed. 2, 220.) 



bb. Cheeks covered with fine scales; opercles with larger ones. 



c. Head very slender, with long acuminate muzzle ; jaws nearly equal; space be- 

 fore dorsal scaled; lat. 1. 65 to 70; lateral blotches small, quadrate. 



72. A. pfroxoccplaaius (Nelson) Cope & Jordan. 



Body rather slender, compressed. Head extremely long, narrow and 

 tapering, the snout very acuminate. Mouth large, the maxillary reach- 

 ing to the eye ; the lower jaw unusually narrow and long, scarcely shorter 

 than upper. Eye about equal to snout, 4^ in head. Cheeks, opercles, 

 and neck -with small scales; chest naked. Color yellowish brown, some- 

 what as in A. aspro, but the lateral spots smaller and more numerous, 

 quadrate in form ; a small blackish spot at each end of the lateral line. 

 Head 4; depth 5. D. XII-1S ; A. II, 9; scales 12-68-14. L. 4 inches. 

 Indiana to Kansas; not common. 



(Etheostoma phoxocephalum Nelson, Bull. Ills. Mus. Nat. Hist, i, 35, 1876; Jordan, 

 Man. Vert. Ed. 2d, 221.) 



cc. Head stouter, with wider muzzle; lower jaw included. 

 7 3. A. aspro Cope & Jordan Slack-sided Darter. 



Body rather elongate, fusiform , compressed behind. Head moderately 

 elongate, less pointed than in some of the species. Mouth moderate, 

 the lower jaw included ; maxillary reaching just past the front of the 

 eye. Eye about equal to snout, 4 in head. Gill-membranes little con- 



