t 
966 FISHES—PEROIDA. 
Body moderately elongate, fusiform, not translucent ; head small, narrowed forwards, 
the profile convex; mouth small, horizontal, the lower jaw included; premaxillaries 
protractile; maxillary not joined to preorbital, except at its insertion; vomerine teeth 
present; scales large; lateral line continuous (rarely wanting on two or three scales) ; 
belly with ordinary scales; gill-:membranes little connected ; dorsal spines 7-10, slen- 
der; soft dorsal much larger than anal ; anal normally with a single, short, slender 
spine, the first soft ray simple but articulate; vertebra (B. nigrum) 17 + 20; coloration 
olivaceous and speckled, the males with head black in spring; size small. 
ANALYSIS OF SPECIES OF BOLEOSOMA. 
a. Second dorsal with 11 or 12 rays; cheeks and breast mostly naked; lateral line 
with more than 40 scales, its pores usually wanting on 3 or 4 posterior scales. 
NIGRUM. 
aa. Second dorsal with be or 14 rays; cheeks scaly ; breast naked; lateral line com- 
plete. : . ° ; : : : : OLMSTEDI. 
183. BoLEosoMA NIGRUM (Rafinesque) Jordan. 
sohmnmy Darter. 
Etheostoma nigra, RAFINESQUE, Ich. Oh., 1820, 37. 
Boleosema nigrum, JORDAN, Bull. U.S. Nat. Mus., x, 1877, 15. 
Boleosoma maculatum, AGASSIZ, Lake Superior, 1850, 305.—JORDAN, Man. Vert., ed. 2, 1, 
1859, 77.—FoRBzES, Bull. Ills. Lab. Nat. Hist., i, 1878, 40, and of many authors. 
Boleosoma olmstedi var. brevipinne, Corr, Journ. Ac. Nat. Sci. Phila., 1868, 214. 
Boleosoma brevipinne, COPE, Proc. Am. Philos. Soc., 1870, 278. 
Boleosoma mutatum, VAILLANT, Recherches var. les Poiss. d’Eau Douce, 1872, 88. 
Description.—Body fusiform, slender; head conical, moderate, the snout somewhat de- 
curved ; mouth small, lower jaw included; cheeks and breast naked (specimens occa~ 
sionally found with these regions closely scaly); opercles scaly ; space before dorsal 
mostly scaled ; fins high, but smaller and lower than in the other species; 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 for- 
ward from eye, and sometimes a line downward also; fins barred; males in the spring 
blackish anteriorly, sometimes almost entirely black; tubes of the lateral line obsolete; 
on the last, 4 or 5 scales; head 44; depth 5; D. IX-12; A. I, 8; scales 5-51-9. Length — 
24 inches. ° 
Habitat, Great Lake region and Mississippi Valley; abundant everywhere in the 
Northwest; found in nearly every stream of Ohio. 
Diagnosis—F rom the other Darters, the genus Boleosoma may be known 
by its speckled coloration and ‘absence of distinct anal spines. From its 
congerer, B. olmstedi, B. nigrum may be known by the small second dor- 
sal of but 12 rays, and by the naked cheeks. The two forms, however, 
undoubtedly are subject to intergradation. 
Habits—This species lurks on the bottom in clear, small brooks, mov- 
