378 



SYNOPSIS OF THE CYPRTNIO/E OF PENNSYLVANIA . 



I have only seen this fish from a tributary of the Concstoga, near Lancaster, Pennsylva- 

 nia, which it inhabited with Argyrcus, Semotilus, etc. 



THOTOGENIS, Cope. 



This genus is the ally of Hybopsis, from which it differs in the sharp-edged pharyngeal 

 teeth, which contrast with the marked masticatory dentition of the latter. The mandible 

 is projecting and the mouth oblique, while in Hybopsis the mouth is usually horizontal 

 or slightly inferior ; in II. haomaturus, however, it is terminal, and in H. hcterodon and 

 H. plumbeolus (Alhurnops, m. 1. c, 282) oblique, and the under jaw slightly projecting. 

 It is therefore probable that further investigation will be necessary to establish this, as 

 well as the allied genera, on firmer bases, though their recognition is not difficult with 

 present material. 



Scales 5 — 39 — 3 ; depth one-sixth length to base of caudal ; equal from muzzle to preoperele ; vontrals far short 

 of anus; dorsal immaculate, a lateral satin band; lateral line little decurved. leucops. 



Scales 7 — 35—3 ; depth four and three-quarters to base of caudal, equal from muzzle to front of opercle ; ven- 

 trals not to anus; dorsal fin unspotted; sides" and below silvery; lateral lino much decurved. ariommus.* 



Scales 6 — 38 — 2 ; depth one-fifth length to base of caudal, equal from muzzle to middle opercle ; ventrals to 

 anus ; dorsal with black spot behind ; no lateral satin band. SPlLOl'TERUS.'j' 



* Photogenis ariommus, Cope, sp. nov. 



This species resembles at first sight the Ph. leucops, but is less Alburnus-liko. On comparing with an example 

 of the latter, .25 longer, the depth of the body is the same, and the eye strikingly larger; the depth of the head 

 the same, and the muzzle shorter. 



Tn this fish the oporoulum is deeply concave on its upper posterior margin, and the inferior is shorter than the 

 anterior; in P. leucops the former is straight, and the inferior border equal the anterior. The dark lateral lino is 

 faint or wanting in the ariommus, and there is no black vertebral band. Placed alongside of a Hypsilepis cornu- 

 tus of equal length, this fish is less deep, and has an eye of almost double the area, besides the different coloration 

 and generic features of teeth and scales. 



Eye two and three-fifths in length head; muzzle two-thirds its diameter; mouth large, mandible scarcely pro- 

 jecting, maxilla not attaining anterior margin of orbit. Frontal breadth three-fifths orbit. Pectoral fins reaching 

 three-quarters distance to ventrals. Depth caudal peduncle one-third from middle origin caudal to opposite first 

 anal ray. Basis of anal slightly elongate, four-fifths height of same, equal basis dorsal; latter equal two-thirds 



height of dorsal ; last dorsal ray much loss than half first, hence the outline of the fin is very oblique. Caudal 



■ 

 deeply furcate, length equal that of head. 



Light olivaceous sides and below silvery, becoming a band with superior dark edge on caudal peduncle. Sides 

 of head and muzzle white. Total length 2.875 inches; base of dorsal to superior base caudal P06 inches; same 

 to end muzzle 1.19. 



f Photogenis spilopterus, Cope, sp. nov. 



