966 FISHES — PEECID^. 



Body moderately elongate, fusiform, not translucent ; bead small, narrowed forwards, 

 the profile convex; month small, horizontal, the lower jaw inolnded; 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 ; vertebrae (-B. nigrum) 17 + 20 ; coloration 

 olivaceous and speckled, the males with head black in spring; size small. 



Analysis of Species of Bolkosoma. 



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 13 or 14 rays ; cheeks scaly ; breast naked ; lateral line com- 

 plete. ........ OLMSTEDI. 



133. BoLEOSOMA NIGRUM CRafinesque) Jordan. 



Johnny Darter. 



Mtheostoma nigra, Eafinesqtje, loh. Oh., 1820, 37. 



BoUos*ma nigrum, Jordan, Bull. U. S. Nat. Mus., x, 1877, 15. 



BolmaomM maculatum, Agassiz, Lake Superior, 1850, 305. — Jordan, Man. Vert., ed. 2, 1, 



1859, 77.— Forbes, Ball. IDs, Lab. Nat. Hist., i, 1878, 40, and of many authors. 

 Boleoaoma olmstedi var. hrevipinne, Cope, Joum. Ac. Nat. Sci. Phila., 1868, 214. 

 Boleosoma irevipinne. Cope, Proc. Am. Philos. Soc, 1870, 273. 

 Boleoaoma mutatum, Vaillant, Becherches var. leg Poiss. d'Ean Donee, 1872, 88. 



Deae/ripUon. — Body fusiform, slender ; head conical, moderate, the snout somewhat de- 

 curved ; montli small, lower jaw inclnded ; dieeks 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 ; tabes of the lateral line obsolete ; 

 on the last, 4 or 5 scales ; head 4i ; depth 5 ; D. IX-12 ; A. I, 8 ; scales 5-51-9. Length 

 2i inches. 



Habitat, Great Lake region and Mississippi Valley; abundant everywhere in the 

 Northwest ; found in nearly every stream of Ohio. 



Diagnosis. — Prom 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- 



