284 FISHES or Illinois 



Key to the Species of HADROPTERUS found in Illinois 



a. Gill-membranes not broadly united at isthmus, distance from tip of snout to 



angle formed by their union scarcely exceeding that to back of orbit. 



b. Color pattern transverse, consisting of (1) bars or bands, or (2) of blotches 



and transversely rather than longitudinally arranged marblings. 



c. Sides with about 15 blotches, some of them extending upward and down- 



ward so as to form ill-defined bars; cheeks scaled evermanni. 



cc. Sides with about 7 broad transverse bars, extending from below lateral line 



on one side, across iback and down on other side; cheeks naked evides. 



bb. Color pattern longitudinal, the sides marked with a median row of blotches 



or a moniliform band, above which are longitudinally disposed marblings. 



d. Scales 8-10, 64-70, 9-11; cheeks scaled aspro. 



dd. Scales 6, 52-60, 6; cheeks naked ouachitae. 



aa. Gill-membranes united at isthmus in a broad curve, least distance from 



muzzle to free margin of gill-membranes 1% to 1% times that from muzzle 

 to back of orbit. 



e. Head very slender and snout long and pointed, 1% times eye; interorbital 



space narrow, its width twice in snout; lateral blotches small and as a 



rule faint; a very small central caudal spot phoxocephalus. 



ee. Head and snout less slender, the latter equaling eye; interorbital space 

 broader, less than 1% times in snout; sides with 8 or 9 large and distinct, 

 often more or less confluent, dark blotches; base of caudal with 3 dark 

 blotches, the central and lower spots usually more or less merged, .scierus. 



HADROPTERUS EVERMANNI Moenkhaus 



Moenkhaus, 1903, Bull. U. S. Fish. Comm., Vol. 22, 397-398. 



Length of single specimen in our collection 3 inches; body stoutish, only 

 moderately elongate, and very little compressed, the cylindrical form suggest- 

 ing Percina caprodes; depth 5.17 in length; greatest width of body about % 

 of its depth; caudal peduncle short and stout, its depth 2.35 in its length. 

 Color (in preservative) light olive with numerous blotches and marblings; 

 back with about 6 large and more or less quadrate dark blotches; sides with 

 13 or 14 blotches, some of them extending upward and downward so as to 

 form ill-defined bars, the dark markings above blotches being of a general 

 transverse rather than longitudinal pattern (as in H. aspro) ; first dorsal with 

 membranes dusky at base, especially toward back of fin; tips of last rays and 

 membranes dusky; soft dorsal and caudal faintly barred, other fins plain; 

 head smoky olive, a prominent dark vertical streak below eye. Head rather 

 short, bluntly conic, 4.08 in length; width of head 1.79 in its length; in- 

 terorbital space flat, 5.76 in head; eye oblique, 3.58; nose 2.97; mouth moder- 

 ate, the maxillary scarcely reaching to orbit, cleft 3.17 in head, lower jaw in- 

 cluded; gill-membranes noticeably but not at all broadly connected at isthmus, 

 the distance from muzzle to angle about 1.1 times that to back of orbit. 

 Dorsal fin XIII, 14; spinous and soft portions scarcely separated; height of 

 first dorsal 1.7 in head, of second 1.6 (height of first 91 per cent, of second); 

 caudal truncate; anal II, 12; pectorals 1.1 in head; separation of ventrals 

 slightly greater than their width at base. Scales 8, 69, 8 [12]*; no pores 

 lacking; cheeks with about 6 rows of rather large scales; opercles and nape 

 fully scaled; breast naked; belly naked anteriorly, a median row of im- 

 mature caducous plates behind. 



* Number in brackets is count to middle line of belly; first count is to front of anal. 



