1908.] NATURAL SCIENCES OF PHILADELPHIA. 521 



about midway between front eye margin and caudal base, reaching 

 vent close before anal. 



Color in alcohol faded dull or pale brownish, belly and below slightly 

 silvery-white. Faint trace of dark streak from eye to caudal base, 

 another from upper side of head back to upper caudal peduncle surface 

 hardly evident, fading out behind though possibly joining lower? 

 Fins all faded pale whitish. Iris leaden-white. 



Length about 2 inches (caudal slightly damaged). 



No. 22,116, A. N. S. P., cotype (type) of C. eos Cope. ]\reshoppen 

 Creek, Susquehanna Co. (Cope). 



Also Nos. 22, 117 and 22, 118, same data, shoTving: Head 3f; 

 depth 4f to 4f ?; D. iii, 7, i; A. iii, 7, i; scales 76 to 82 + 5; 26 scales 

 transversely; snout 3^ to 4 in head; eye 3 to 31- ; maxillar}^ 3^ to 3^; 

 interorbital 3^ to 3^; teeth 5-5; length If to l|f inches. 



This fish is only known to me from the above examples, though 

 Cope mentions 4, all of which were taken in September of 1861. Noth- 

 ing is known of the species, aside from Cope's short description. 

 Hybognathua nuchalis Agassiz. 



Recorded by Cope. Occurs west of the Alleghanies. I have no 

 examples. 



HybognathuB nuchalis argyritis (Girard). 



H. nuchalis Fowler, Ain. Nat., XLI, 1907, p. 8. Kiskiminitas R CNot of 



Ag.) 



Head 3| to 4^; depth 4 to 4^; D. iii, 7, i; A. iii, 6, i; scales 37 

 to 42 + 2; 7 scales above 1. 1.; 4 or 5 scales below 1. 1.; 23 predorsal 

 scales; snout 3^ to 3f in head; eye 2f to 3^; maxillary 3| to 3f ; 

 interorbital 2| to 3; teeth 4-4. Body moderately compressed, some- 

 what fusiform. Head rather short. Snout broadly convex. Eye 

 little elongate, rather large. Mouth rather wide. Maxillary to eye. 

 Preorbital broad, width f its length. Rakers 2 + 7? short weak 

 points. L. 1. median. Dorsal origin about midway between front 

 nostril and caudal base. Anal behind dorsal base. Caudal apparently 

 little emarginated. Pectoral about f to ventral, latter inserted trifle 

 before dorsal reaching f to vent. Color largely silvery. Length 1^ 

 to 2 inches. Four examples from the Kiskiminitas R. (Cope). 



This fish is closely related to H. nuchalis, with which I recently 

 confused it, but differs apparently in the much larger maxillary. 

 It occurs west of the Alleghanies and is said to attain a length of 4 

 inches. 



Hybognathus nuchalis regius (Girard). 



Head 4 to 4|; depth 3^ to 4f ; D. iii, 7, i; A. iii, 7, i, rarely iii. 



