BOLEOSOMA TESSELLATED DARTERS 299 



inches; body slender, considerably compressed, greatest width of body about 

 3^ its greatest depth; depth 6.5. to 7.2 in length; caudal peduncle slender, its 

 depth 3.1 to 3.9 in its length. Color much as in B. nigrum, but paler, the 

 side markings less distinctly W-, X-, and V-shaped; color pattern of upper 

 portion of body and back more open, being less densely and finely tessellated 

 than in the preceding species; back with 5 or 6 saddle-like blotches, the 

 corners of which are more or less distinctly connected by dark markings, 

 giving the fish the appearance of being marked dorsally with a chain of rings, 

 which are dark or light according as the eyes are focused on the saddle-like 

 dark blotches and their connecting bands, or on the circular light areas in- 

 tervening; an evident dark spot on opercles; a conspicuous zigzag streak on 

 nose in front of eye and a very faint suborbital bar; dorsal and caudal faintly 

 barred. Head 3.9 to 4.3, slightly shorter and considerably narrower than in 

 B. nigrum, its greatest width 2 to 2.5 in its length; interorbital space flat, 5.2 

 to 6.6 in head; eye round, 3.3 to 4 in head, not protruding above the cranium; 

 nose bluntly romided, less decurved than in B. nigrum, 3.8 to 4.5; mouth rather 

 small, maxillary to front of pupil, cleft 3.1 to 3.8 in head; lower jaw included; 

 gill-membranes not broadly connected, distances to angle and to back of orbit 

 equal. Dorsal fin VIII-X, 10 or 11 (usually IX-10); spinous and soft por- 

 tions well apart, separated by a distance about equal to diameter of eye; 

 height of first dorsal 1.7 to 1.9 in head, second 1.4 to 1.7 (height of first 70 to 

 90 per cent, of second) ; caudal shghtly emarginate; anal I, 7 or 8; pectorals 1 

 to 1.3; separation of ventrals as a rule considerably less than their width at 

 base. Scales 6, 52-60, 6 or 7 [7-10]; lateral line ordinarily developed on only 

 about half the scales; cheeks, opercles, and breast fully scaled; nape with a 

 median naked strip; belly covered with ordinary scales. 



This rather insignificant but interesting Httle darter is one 

 of the more distinctly southern species of the group. Although 

 it has been taken b}" us in Illinois as far north as South Chicago 

 on the east and Green River, in Henry county, on the west, 

 our southern Illinois collections preponderate greatl}^ in number 

 over those of central or northern Illinois, the relative frequencies 

 being 2.44, .46, and .10 for these three sections of the state. 

 Like its nearest relative, the Johnnj' darter, it is essentially a 

 species of creeks and the smaller rivers, it we may judge by our 

 107 collections; but it is found more frequentl}^ than that species 

 in standing water, especiall}' in the lakes and ponds of the river 

 bottoms, and much more frequently also in rivers of the largest 

 class — thirty times, for example, from Havana and Meredosia, 

 where Boleosoyna nigrum was obtained but twice. It is most 

 abundant in the Big Muddy and the Saline River basins, occur- 

 ring in the first in seven out of nine collections, and in the 

 second in eleven out of eighteen. It is especially peculiar in the 

 fact that more than two thirds of our material was taken from 

 quiet waters, and about three fifths of it from waters with a 

 muddy bottom. In geographical and local distribution and in 



