548 PROCEEDINGS OF THE ACADEMY OF [DeC, 



high, midway in head. Mouth small, broad. Maxillary to hind 

 nostril, small barbel at end. Slightly convex interorbital broad. 

 Rakers 2 + 5 robust firm short points. Scales smaller anteriorly 

 on trunk. L. 1. complete, slightly decurved, nearly midway. Dorsal 

 origin about midway between front nostril and caudal base. Anal 

 inserted little behind dorsal base. Caudal forked, lobes about equal. 

 Pectoral | to ventral, latter inserted little before dorsal, fin to vent. 

 Color olivaceous above, sometimes nearly blackish with mottled 

 appearance. No distinct dusky lateral shade in adult, more evident 

 in young. Lower surface whitish. Sometimes blackish opercle blotch. 

 Lips, cheeks and lower fins in spring males rosy-red. Iris silvery. 

 Spring males also with entire upper head, pectoral fin and trunk 

 finely tuberculate, jaws smooth. Length 1\^ to 3y\ inches. Many 

 examples from the Delaware R. basin at Kennett Square, Mendenliall 

 and Mill Run (Chester Co.), the Susquehanna R. basin at Paradise 

 (Lancaster Co.) and Meadow Run in the Youghiogheny R. basin near 

 Ohio Pyle (Fayette Co.). 



This dace occurs in clear swift streams, usually about rapids and 

 deep pools, in all the upland waters of the State. It is said to reach 5 

 inches in length and be good bait for bass, though rather difficult to 

 secure. I have usually found it associated with R. atronasus, though 

 it appears to be more active. 

 Rhinichthys atronasus (Mitchill). 



Head 3 to 4|; depth 3f to 5}; D. iii, 7, i, rarely iii, 6, i or iii, 8, i; 

 A. usually iii, 6, i, rarely iii, 7, i; scales usually 50 to 60, varying 

 frequently 43 to 49 and 61 to 64, rarely varying 39 to 42 and 65 to 67 + 

 usually 3, occasionally 2 or 4; scales above 1. 1. usually 12, frequently 

 11 or 13, seldom 10, rarely 14; scales below 1. 1. usually 8, frequently 9, 

 seldom 7 or 10, rarely 11; predorsal scales usually 30 to 33, frequently 

 28, 29 or 34 to 38, seldom 25 to 27, rarely 23 and 39 to 42; snout 2^ 

 to 3^ in head; eye 3 to 5^; maxillary 3 to 4; interorbital 2^ to 3f ; 

 teeth 2, 4-4, 2 usually, rarely 2, 5-4, 2 or 2, 4, 1-4, 2 or 2, 4-3, 2 or 1, 

 3-4, 2. Body compressed, moderately long. Head moderate, robust, 

 broad. Snout convex, depressed, length | its width. Eye small in 

 adult, large in young, circular, high, slightly anterior. Mouth small, 

 inferior, snout projecting about ^ of eye beyond mandible. Maxillary 

 little inchned, to front nostril, ending in short barbel. Interorbital 

 broadly depressed. Rakers 3 + 4 short firm points. Scales small, 

 well exposed. L. 1. complete in adult, absent in young. Dorsal origin 

 midway between hind eye margin and caudal base. Anal origin just 

 after dorsal base. Caudal forked, lobes rounded. Pectoral | to ven- 



