196 Cockerel! und Callaway — Fi><hcs of the Gcnits Notropis. 



No such spot at ])ase of caudal iiu ; sculpture of scales distinct. 



Snout shortest of the four southern sju'cies .... N. swaini Jordan. 



Comal Springs, New Braunfels, Texas. 

 Snout the most pointed of the four southern species; scales very sil- 

 very i\^ stilhitis Jordan. 



Clinch River, Tenn. 

 The species separate on scale characters thus : 



Scale longer than hroad 1 . 



Scale ahout as l>road as long; radii far apart and irregular . X. slilbms. 

 Scale broader than long -. 



1. Sculpture very strong; radii all complete, far apart, S to 10 . y.jejvmis. 

 Sculpture not strong; railii not all complete, to 9 . . . A', leiiciodiis. 



2. Sculpture strong. 



Scale very large, circuli irregular, nucleus 3^' from center, radii 10 



or 11 -V. arge. 



Scale large, radii 11 or IL', \videai)art; lateral, circuli remarkably 



wide apart .... X. scopifer Eignni. i^ Eignm. 



North Dakota. 

 Scale medium, radii 7 to 10; circuli n>gular; nucleus ^^ from base 



X. atherinoides. 

 Sculpture distinct but not strong, radii '.» or 10; nucleus i from base; 



scale covered with skin -V. sirarni. 



Sculpture weak.; radii 5 to 7, far apart; circuli regular; nucleus I4 



from l)ase X. tclrscopus. 



AVe have considered whether this large genus might be subdivided. It 

 would be possible to separate Luxilus; but inasmuch as most of the other 

 su})genera a]ipear to radiate from this type, it would apparently be necessary 

 to regard nearly all of them as independent genera, if any. Perhaps at 

 some later date, with more experience and better materials, a division of 

 the genus may l)e undertaken, but it does not seem practicable at present. 

 For nearly all the specimens used in this paper we are indel^ted to the 

 U. S. Bureau of Fisheries. 



