NOTROPIS 



NOTROPIS PILSBRYI FOWLEB 



Fowler, 1904, Proc. Acad. Nat. Sci. Phila., LVI, 245-247. 



Fishes intermediate between those forms typified in Illinois by N. 

 cornutus on the one hand and N. atherinoides and rubrifrons on the other, 

 and possessing resemblances to both. Readily distinguished from the first 

 by the rounded and loosely imbricated scales of the sides and by the backward 

 insertion of the dorsal fin, and from the latter by the difference in general 

 proportions (the present species being much shorter and deeper), and by the 

 presence (as in N. cornutus) of a broad dark streak along the mid-dorsal line. 



Length 2% inches; form robust, the body deep in front of dorsal and 

 moderately compressed; back elevated, the upper and lower outlines tapered 

 evenly to the tip of the pointed snout, much as in Hybognathus nuchalis; 

 depth 4 to 4.4 in length; caudal peduncle but little shorter than head, more 

 slender than in N. cornutus, its depth 2.3 to 2.5 in its length. Color in life 

 not known; in spirits, a dusky olive above, the scales rather densely specked 

 over their entire surface and not distinctly dark-edged; sides below lateral 

 line and belly silvery, unspecked; a broad dusky band along side, interrupted 

 on opercle and in eye (in preserved specimens), but faintly apparent before 

 eye to end of snout, tipping chin; a broad and distinct dark vertebral streak; 

 dorsal and lower fins pale; caudal somewhat dusky. Head conical, 4 to 4.3 

 in length, the muzzle pointed and profile slightly angled at nape; width of 

 head 2 to 2.1 in its length; interorbital space nearly flat, 2.9 to 3.1 in head; 

 eye 3.4 to 3.5 in head, slightly less than snout; nose 3.3; mouth rather large, 

 oblique, tip of upper lip above lower margin of orbit; maxillary longer than 

 eye, 2.8 in head, barely reaching front of orbit; jaws subequal; isthmus less 

 than pupil. Teeth 2, 4-4, 2, compressed and hooked, the grinding surface 

 developed as an extremely narrow groove on at least two of the teeth; peri- 

 toneum densely and coarsely specked with brown. Dorsal fin with 8 rays, 

 inserted distinctly behind ventrals, its first ray farther from muzzle than 

 base of caudal; longest dorsal ray 1.3 to 1.5 in head; anal rays 9 or 10; pectorals 

 % to ventrals, 1.3 in head; ventrals quite reaching vent. Scales 6, 37 or 

 38, 3 or 4, large, cycloid and loosely imbricated, not notably deeper than 

 long on sides and not crowded anteriorly; the rows appearing to "run out" on 

 back behind dorsal as in N. cornutus; lateral line decurved anteriorly, com- 

 plete; 15 scales before dorsal fin. 



Sexual differences not known, the three specimens from 

 Illinois which were taken on May 30 (1901; Ac. No. 28174) 

 being males with sexual organs considerably developed but 

 without tubercles. 



Found in this state only from the East Fork of the Mazon 

 River, near Gardner. The identity of this species with N. 

 pilsbryi Fowler, which was described in 1904 from the White 

 River basin in Arkansas, seems open to no question. 



