Vol. XXII, pp. 189-196 December 8, 1909 



PROCEEDINGS 



(IF THF, 



BIOLOGICAL SOCIETY OF WASHINGTON 



OBSERVATIONS ON THE FISHES OF THE GENUS 



NOTROPIS. 



BY THEODORE I). A. COCKERELL AND ()TI8 CALLAAVAY. 



From our study of the scale-characters of the smaller Ameri- 

 can minnows, combined with those already known, it appears 

 that Notropis must have evolved on the North American conti- 

 nent, from some member of the Pimepha]ina\ The transition 

 is from Pimephdles to Cliola, and thence to the subgenus Luxilus 

 of Notroj^is, especially N. cormitus. This indicates an origin for 

 this series independent of the true Leuciscina?, which must have 

 come from the Old World. According to this view Notropis 

 typifies a distinct subfamily Notropina:", to include Notropis and 

 Cliola, witli IT]/hopsis and perhaps Phenacobiiis forming an aber- 

 rant brancli. (Nocoiins kentuckiensis has a very distinct multi- 

 radiate scale, and must be excluded from Hi/hojms.) 



Cliola smithii Evermann & Cox (the only species of this genus 

 we possess) has the peritoneum red-brown (not spotted), on a 

 silver substratum, just as in Orthodon and Acrocheilus. The fish 

 is rather deep-bodied, with rather large scales, approaching 

 Luxihts. The gill-lamellfe are very strongly fiml)riate. The 

 scales are broad, with numerous (about 19) apical radii, herein 

 agreeing with the Pimephalina^ and with Luxilus. 



The transition to Lvxllus is thus sufficiently evident. N. 

 cormitus represents the stem-form of Kotrojns, and yet is abun- 

 dant and wide-spread, showing that it was no failure of this type 

 that led to the production of so many offshoots. The numerous 

 species of Notropis seem to be a product of the exuberance of 

 their race, and it may be surmised that some of the minor forms 

 are quite recent, even perhaps post-glacial. In some cases the 

 small size and slender body may doubtless be regarded as an 



31— Proc. Biol. Soc. W.\sh., Vol. XXII, 1909. (189) 



