386 REPORT OF THE COMMISSIONER OF FISHERIES. 



sess more or less dermal pigment and thus are colored much like ordi- 

 nary fishes. There are four pj'ioric coeca, and each species possesses 

 tactile ridges. 



KEY TO THE SPECIES OF CHOLOGASTER. 



a. Eye large, contained 5.5 times in the head; species of dark coloration. 

 . h. Sides with 3 well-defined longitudinal lines, the middle one broadest; tactile 



papillpe very small , cornutus. 



bb. Dark lines present on the sides of the body but much fainter than in cornutus; 



tactile papillae large ■pap'dllferus. 



aa. Eye very small, contained 10 times in the head; coloration faint agassizii. 



Chologaster cornutus Agassiz. 



The body of this species is rather slender, its length being contained 

 from 5.25 to 6.5 times in its length; head considerably depressed, 3 to 

 3.5 in body; mouth large, terminal, oblique, the lower jaw projecting; 

 maxillar}^ extending to near front of eye; eye small, about half length 

 of snout and so located as to be able to see upward as well as side wise; 

 gill-membranes united and loosely joined to the isthmus, reaching back 

 to or covering the vent; pectoral 1.5 in head and l.-i in distance from 

 snout to front of dorsal fin; caudal fin considerably pointed, about 

 equal to head; dorsal with 8 to 9 rays, its front nearer base of caudal 

 than tip of snout; anal with 8 to 9 ra3"s, inserted almost directly 

 under dorsal; scales very small, C3"cloid and not arranged in regular 

 ^^ rows; no lateral line; tactile ridges pres- 



-rTrrrl"^ ^,^-.,,5^™^ eut but vcry small; about 70 scales in a 

 "^^'^^ - — ■-- ----I--^-^-^^3ii^ straight line along side from head to 



^ .. ., , ^^ caudal fin; head naked. Color dark 



Cut 11. — Cholot/aster cornuttts. 



brown above, lighter on sides and white 

 on belly; side with 3 narrow, well-defined longitudinal dark lines, the 

 middle one, which is deepest and widest, extending across head and 

 eye to tip of snout, upper line nearer to back than to middle line; a 

 dark black blotch on base of caudal; remainder of caudal variously 

 mottled with black. There is sometimes a white crossbai' about the 

 middle of the caudal, but this ma}"- be reduced to 2 small white spots; 

 tip of fin frequently white. In some specimens the back is entirely 

 black and the dorsal fin white, spotted with black. The color, no 

 doubt, varies much with the conditions. Length of the largest speci- 

 men known, 1.8 inches. 



This little fish inhabits the swamps of the southern United States 

 from the Dismal to the Okefinokee. It is said to be abundant locally, 

 but at present there are very few specimens in the museums, so far as I 

 am able to learn. Those examined were from the Dismal Swamp, Vir- 

 ginia, and were kindl}^ loaned by the United States National Museum. 



The specimens described as O. avitus prove to be a variation of C. 

 cornutus, the difference being chiefly one of color. « 



« Jordan and Evermann, Fishes of North and Middle America, I, 703, 1896. 



