38 Proceedings of the Biological Society of Washington. 



17. Notropis procne (Cope). 



This species appears to be common in the small streams, being especially 

 abundant in Swan Creek. A few examples were taken at Lapidum and 

 Heron Run. 



In our examples of this species the scales of the back are narrowly 

 edged with brownish, forming a very distinct cross-hatching. Lateral 

 band dusky, not (or indistinctly) continued around tip of snout. Lateral 

 line complete. Six divided l'ays in anal fin. 



18. Notropis bifrenatus (Cope). 



Our examples of this species were seined on the beaches of the Sassafras, 

 Elk, Bohemia and Susquehanna Rivers, where it seems to be common. 

 None were taken in the small creeks, where N. procne was abundant. 



In our examples the dusky edging of the scales of the back is continued 

 onto the body of the scale, the cross-hatchings being much less distinctly 

 outlined than in N. procne. Lateral band darker than in N. procne, and 

 continued distinctly around tip of snout. Lateral line incomplete. Six 

 divided rays in anal fin. 



In alcoholic examples of this and the preceding species, the black 

 edgings to the scales immediately above the dark lateral band are absent, 

 giving the appearance of a light band above the dark one. 



19. Notropis hudsonius amarus (Girard). Gudgeon. 



Everywhere abundant. Lateral band silvery or leaden, with traces of 

 a blackish blotch at base of caudal. No light band above this stripe. 

 Lateral line continuous; anal rays 7 (rarely 8). 



20. Notropis analostanus (Girard). 



Mostly confined to the small creeks, and especially abundant in the 

 old canal at Lapidum, Maryland. 



21. Notropis cornutus (Mitch ill). 



Taken only in Swan Creek and in the old canal at Lapidum, in both 

 of which places it was abundant. 



Two males (10.1 and 11 cm. in length) in breeding dress, had in addi- 

 tion to the tubercles on head and nape, smaller tubercles arranged in 

 rows on the upper surface of the pectorals. 



22. Notropis photogenis amoenus (Abbott). 



This species, which we have taken in large numbers in several of the 

 tributaries of the Potomac near Washington, D. C, appears to be less 

 abundant here, only three examples being taken, one from Swan Creek 

 and two from Lapidum. 



23. Rhinichthys atronasus (Mitchill). 

 Ten examples were taken in the rocky pools of Heron Run. 



