SYNOPSIS OF THE CYPKTNTDiE OF PENNSYLVANIA. 



388 



Of the above species which do not enter our limits : 



Hybopsis stramincus is Hybognathus stramineus in Proc. Acad. Nat. Sci., Phila., 1864, 

 283. In the description of this species, 1. c, the position of the dorsal fin is erroneously 

 described, and is as now corrected. A number of specimens also from Detroit River, ex- 

 hibit a vertebral band from nape to caudal fin. 



H. heterodon, Alburnops heterodon, Cope, 1. c, 281. The variation in the structure of 

 the teeth which I have mentioned under the original description, may be thus accounted 

 for : the crcnatc teeth arc immature, as occurs in other genera ; those without masticatory 

 surface are rare, perhaps also immature. 



H. regius, Hybognathus regius, Girard. Tins species has strongly-hooked teeth, as ex- 

 hibited in preparation in Museum Surgeon-General, Washington, 1). C, and the mouth is 

 scarcely inferior, hence neither a Hybognathus nor typical Hybopsis. 



H. volucellus, Hybognathus volucellus, Cope, 1. c. 



Albumus nitidw, Kirtland, Cleveland Annals Science, probably belongs also to Hybopsis. 



HYBOPSIS CHALYBAEUS, Cope. 



Head 3.8 (sometimes 4) times in length to base of caudal; length of latter equal from opercular margin to 

 nares. Muzzle shorter than diameter of orbit, slightly acuminate, and exceeded by the tip of the mandible when 

 viewed from above; head flat above, less angulate on the temporal region than many species, the superior plane 

 narrower there than between the orbits ; supraoporcular region oblique. Teeth slightly hooked, masticatory sur- 

 face well marked, upper tooth nearly opposite angle of the ala. Dorsal fin elevated, with eight rays a very little 

 behind above ventrals; latter pointed, reaching anal. Anal slightly elongate, exceptionally with nine rays; pec- 

 torals pointed, not reaching ventrals. Superior outline rising to dorsal fin, then immediately descending, form- 

 ing with the nearly parallel ventral line, the elongate caudal peduncle. Caudal fin deeply forked. 



The broad burnished black lateral band does not descend below the lateral line on the middle of the body ; it 

 occupies one and two half rows of scales. Above it on head and body the color is fulvous brown, excepting a 

 straw-colored crescent from orbit to orbit round the nose; terminal half of mandible black ; sides of head below, 

 silvery, of body straw-colored; no distinct vertebral stripe, or spots on the fins. 



This is a very small species, nearly the smallest of the Cyprinidai ; a specimen before me, apparently fully 

 grown, measures only 1 inch 8.5 lines in total. 



Several specimens of this species were taken in a tributary of the Schuylkill Iiiver, near 

 Conshohocken, by Charles H. Darlington, and the museum of the Academy possesses 

 numerous others. 



This species is most allied to the H. heterodon, and in less degree to the H. procne ; 

 very careful examinations of large numbers of specimens of the three convince me of the 

 value of the characters adduced. 



1 have satisfied myself that the II chalybaeus cannot be the fry of any species known 



