1910.] NATURAL SCIENCES OF PHILADELPHIA. 273 



NOTES ON THE VARIATION OF SOME SPECIES OF THE GENUS NOTROPIS. 



BY HENRY W. FOWLER. 



In this paper the results of the range of variation in the important 

 or fundamental characters of a majority of the species of this genus 

 are presented. Most all of the material examined in this connection 

 is exclusive of that already published in my Synopsis of the Cyprinidse 

 of Pennsylvania, and is contained in the collections of the Academy 

 of Natural Sciences of Philadelphia. Many of the specimens are the 

 types of Girard and Cope and as the published accounts and figures 

 are insufficient or incomplete, it is hoped that the notes and figures 

 given upon each species will be of use in future determinations. Little, 

 if any attention, in most cases, seems to have been paid to the extent 

 of variation in the species of this genus, so that often dogmatic and 

 compiled descriptions of some writers are very unsatisfactory, especi- 

 ally when based on the examination of a single example. The deter- 

 mination of the species is thus often very difficult, especially in such 

 a large genus as the present, and where age, sex and the individual 

 often vary greatly. No attempt is made in any way to alter the 

 limits of the genus from those prescribed by Jordan and Evermann. 



Notropis aztecus Woolman. 



Head 4; depth 3f ; D. hi, 7, i; A. iii, 6, i; scales 46? + 2; 8 scales 

 above 1. 1. ; 6 scales below 1. 1. ; 25 predorsal scales; snout 3 J in head; 

 eye 5; maxillary 3£; interorbital 2|; teeth 4-4; length 3| inches. 

 One from L. Xochimilco, Mex. 



Notropis bifrenatus (Cope). PI. XV, fig. 1. 



Head 3| to 4|; depth 3f to 5f; D. iii, 7, i, rarely iii, 6, i; A. iii, 

 6, i ; scales 28 to 35 + usually 2, frequently 3, rarely 1 ; 5 or 6 scales 

 above incomplete 1. 1. ; 4 or 5 scales below 1. 1. ; usually 12, frequently 

 11, sometimes 13, occasionally 10 or 14 predorsal scales; snout 3£ to 

 4£ in head; eye 2\ to 3J; maxillary 3£ to 44; interorbital 2\ to 3; 

 teeth 4-4; length 1A to 2| inches. Very large series, of which 52 

 examined from Ridgewood, Budd's Lake, Trenton, Turnersville, 

 Pensauken, Mantua, Florence, Crosswicks Creek. N. J. 



