1056 Bulletin 47, United States National Museum. 



1446. BOLEOSOMA NIGRUM (Rafinesque). 

 (JOHNNY DARTER.*) 



Head 3f to 4i; depth 5 to 6; eye 3f to 4 in head, equal to or a little 

 longer than snout. D. IX-12 to 14 (VIII to X-10 to 14); A. I, 7 to 9; 

 scales 5-44 to 55-9, rarely 35 to 40. Body fusiform, slender, little com- 

 pressed. Head conical, moderate, the snout somewhat decurved. Mouth 

 small, lower jaw included. Cheeks and breast naked (specimens occasion- 

 ally found with these regions closely scaly) ; opercles scaly ; space before 

 dorsal mostly scaled. Opercular spine strong ; space between mouth and 

 gill cleft about half head. Fins high ; pectoral about as long as head ; 

 dorsals about equal in height, the spinous a little longer. Anal small, 

 its spine short and weak ; caudal truncate. Coloration pale olivaceous ; 

 back much tessellated with brown ; sides with numerous small W-shaped 

 blotches ; head speckled above, mostly black in the males ; a black line 

 forward from eye and sometimes a line downward also ; fins barred ; 

 males in the spring blackish anteriorly, often almost entirely jet black. 

 Tubes of the lateral line sometimes obsolete on the last 4 or 5 scales. 

 Length 2 to 2 inches. Eastern United States, almost everywhere, espe- 

 cially northward, the typical form (nigrum) throughout the Ohio Valley, 

 Great Lake region, and Upper Mississippi west to Colorado and north to 

 Manitoba ;t very abundant in most streams, especially small ones, among 



*We never grew tired of watching the little Johnny (Boleosoma nigrum, Rafinesque). 

 Although our earliest aquarium friend and the very first specimen showed us by a rapid ascent 

 of the river weed how " a Johnny could climb trees" he has still many resources which we 

 have never learned. Whenever we try to catch him with the hand we begin with all the uncer- 

 tainty that characterized our first attempts, even if we have him in a two-quart pail. We may 

 know him by his short fins, his first dorsal having but 9 spines, and by the absence of all 

 color save a soft yellowish brown, which is freckled with darker markings. The dark brown 

 on the sides is arranged in 7 or 8 W-shaped marks, below which are a few flecks of the same 

 color. Covering the sides of the back are the wavy markings and dark specks, which have given 

 him the name of the "Tessellated Darter," but Boleosoma is a braver name aad we even prefer 

 "Boly" for short. In the spring the males have the head jet-black, and this dark color often 

 extends on the back part of the body so that the fish looks as if he had been taken by the tail 

 and dipped into a bottle of ink. But with the end of the nuptial season this color disappears, 

 and the fish regains his normal strawy hue. The head in Boleosoma resembles that of Diplesion, 

 but the habit of leaning forward over a stone, resting on the front fins, gives a physiognomy 

 even more frog-like. His actions are, however, rather bird-like, for he will strike attitudes like 

 a tufted titmouse, and he flies rather than swims through the water. He will, with much perse- 

 verance, push his body between a plant and the side of the aquarium and balance himself on 

 the slender stem. Crouching cat-like before a snail shell, he will snap off the horns which the 

 unlucky owner pushes timidly out. But he is often less dainty, and, seizing the animal by 

 the head, he dashes the shpll against the glass or a stone until he pulls the body out or breaks 

 the shell. Jordan & Copeland. 



f Specimens obtained by Mr. Woolman from Big Stone Lake, Minnesota, and which may repre- 

 sent a tangible variety, are described as follows: 



Head 3%; depth 5g; eye 4% (4 without flap), equaling snout. D. VIII-12; A. I, 8; scales 

 4-49-5. Resembling the variety olmstedi in the high fins and slender body; head moderate; 

 caudal peduncle long and slender; mouth large, nearly horizontal; premaxillaries protractile, 

 maxillary reaching vertical of pupil; gill membranes scarcely connected. Cheeks naked or 

 nearly so; opercles, nape, and breast scaled; belly with ordinary scales; lateral line complete, 

 slightly arched in anterior portion. Dorsal fin high, the longest spine about 1% in head, the 

 soft portion a little higher; anal rays about 2 in head; anal fin smaller than soft dorsal, its base 

 1| in that of soft dorsal; pectoral long, as long as head, almost reaching anal fin; ventrals short, 

 l%in pectoral. Color of male, in alcohol, dusky, with 10 or 1 1 darker vertical oars extending from 

 median line of back to below lateral line, the anterior ones narrow, those on posterior part of 

 body broader; the spaces between these bars with small darkpunctulations; topandsidesof head 

 profusely punctulate, a dark suborbital spot; spinous dorsal black on membrane connecting first 

 2 or 3 spines, rest of spinous part punctate and edged with black; a small black spot on posterior 

 part; soft dorsal more or less mottled; caudal paler, some black on tip and edges; anal profusely 

 covered with fine dark points, thickest on edge; ventrals blue black; pectorals pale. Length 2 

 inches. Known only from Big Stone Lake, Ortonville, Minnesota, 



