COTTUS — miller's THUMBS 327 



and specked with darker; fins mostly barred or mottled" (Jordan and Ever- 

 mann). All our specimens have evident oblique dusky bars on posterior half 

 of body. Head 3 to 3.5, convex above, the eyes directed outward as much 

 as upward; width of head almost as great as its length; interorbital space 3.8 

 to 5.5; nose 2.8 to 3.4; mouth wide and lips very thick, maxillary 1.7 to 2.1 

 in head, to middle of orbit; upper preopercular spine short, usually less than 

 half eye and rather inconspicuous; lower spines concealed in skin; isthmus 

 1.3 to 1.5 times eye; palatines with teeth. Dorsal VII to IX, 16 to 18; first 

 dorsal scarcely % height of second; caudal spatulate; anal 13 to 15; pectorals 

 to vent. Body entirely destitute of scales; a few prickles, often indistinct, 

 behind pectorals; top of head warty; lateral line continuous or interrupted 

 posteriorly. 



This species inhabits clear, rocky brooks and lakes of the 

 middle and northern United States, ranging from Kansas and 

 the Dakotas to New York and Virginia. In our collections, 

 which number 10 in all, it has been taken only in northern and 

 southern Illinois: once in McHenry county; once from the 

 Du Page near Joliet; six times from rocky spring branches in 

 Union county; and once each in springs in Calhoun and Jersey 

 counties. 



About 25 per cent, of the food of six specimens taken in 

 southern Illinois consisted of small fishes. Aquatic larvae 

 formed about 40 per cent, of the food, and the rest was mostly 

 Crustacea (Asellus). In the clear streams and lakes of the north 

 this fish has been found to be extremely destructive to the eggs 

 and fry of trout. 



COTTUS RICEI Nelson 



Nelson, 1876, Bull. 111. State Lab. Nat. Hist., I. 1, 40. 



J. & G., 694 (Unanidea spilota) and 935 (U. ricei); M. V., 148; J. & E., II, 1952; J., 

 50 (Tauridea spilota); L., 30. 



Length (of our single specimen) 2J4 inches; body rather slender, regu- 

 larly tapered to the very slender caudal peduncle; depth 4.9; width about 

 same as depth; depth caudal peduncle 3.3 in its length. Color (in spirits) 

 brownish olive, sides irregularly and faintly mottled; faint traces of 2 dusky 

 bars on caudal peduncle; last membranes of second dorsal dusky. Head very 

 flat above, the eyes directed nearly upward; width of head equal to its length; 

 interorbital space flat, very narrow, 8.2 in head; nose 3.6 the posterior nostril 

 with conspicuous raised edges, tube-like; mouth narrow, smaller than in last 

 species, and lips thinner, the maxillary scarcely past front of orbit, 2.9 in 

 head; preopercular spine long, 2 /z of eye*; lower preopercular spines short 

 and mostly concealed; the upper spine hooked backward and upward, carry- 

 ing with it the skin of the head in an auricular flap-like appendage, giving 



* Equal to eye. according to Nelson. 



