1998.] NATURAL SCIENCES OF PHILADELPHIA. 535 



lucent, upper slightly brownish. Costal region silvery, merging into 

 plumbeous or grayish longitudinal streak along caudal peduncle side. 

 Each scale of 1. 1. with a number of duskj^-brown points along tubes. 

 Dorsal and caudal pale transparent grayish-dusky, other fins paler. 



Length 2y^g inches. 



Type, No. 31,126, A. N. S. P. Tributary of the Allegheny River 

 above (south of) Port Allegany, McKean County. August of 1904. 

 T. D. Keim and H. W. Fowler. 



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

 A. usually iii, 7, i, rarely iii, 6, i ; scales 33 to 37, usually about 33 + 

 2; scales above 1. 1. usually 6, rarely 5; scales below 1. 1. 4; predorsal 

 scales usually 16, sometimes 15; snout 3^ to 3f in head; eye 3 to 3yV; 

 maxillary 3yV to 3i; interorbital 2f to 2|; teeth 1, 4-4, 1. Length 

 ly| to l|f inches. Tributary of the Allegheny R. at Cole Grove, 

 McKean Co. July 23, 1899. S. P. G. Lindsay and H. W. Fowler. 

 Nos. 24,045 to 24,047, A. N. S. P., paratypes. 



This species seems to be most closely related to N. hudsonius, but 

 differs in the larger and more slender caudal peduncle, different 

 physiognomy, and coloration. It differs from A'', deliciosus and N. 

 boops in the same characters, besides others, such as the eye and fin 

 rays. It differs from N. ariommus, N. scabriceps, N. jejunus and allied 

 species, in the fewer pharyngeal teeth, and other characters in com- 

 bination, when the proper extent of variation is allowed. It may, 

 therefore, be considered a member of the subgenus Hudsonius. 



Only the type was obtained at Port Allegany. At the type locality 

 the stream was of clear cold water, flowing rather rapidly over a shal- 

 low place of considerable extent, and with a bottom of small stones 

 and pebbles. The fish was rather shy, and though several others 

 were seen at the same time, the one secured was rather difficult to 

 capture. They all seemed to lurk about the banks, under large 

 stones, or in the deeper places, and were quite agile in their movements. 

 Coitus gracilis and Semotilus atromacidatus were found in the same 

 places, the latter especially abundant. 



At Cole Grove several small examples were taken some years pre- 

 viously. They were all found in pools, associated with Exoglossum 

 maxillingua and Leuciscus elongatus. In coloration they did not seem 

 to differ much from the type, their caudal lobes being about equal. 



(Named for my friend, Mr. Thomas D. Keim, who assisted me in 

 procuring the type, besides many interesting local collections of fishes 

 for the Academy.) 



