SYNOPSIS OF THE CYPUINIDVE OF PENNSYLVANIA. 



361 



Acerina is to sonic others among Percidse. Its general appearance is that of a small Gobio 

 or a Hybopsis, with the muzzle rather heavier than is usual in either ; but examina- 

 tion shows that, besides the absence of barbels, it is peculiar in that the suborbital and 

 interopercular bones, with the rami of tire mandible, are greatly dilated, and bear septary 

 laminao, which separate mucus cavities, relatively as large as those of Acerina or Percop- 

 sis. They extend in two series ; seven from the postorbital bone to the side of the end of 

 the muzzle, and eight from the same point to the symphysis mandibuli. The muzzle over- 

 laps the mandible ; no cartilage on the latter. Scales large, the usual surface exposed. 

 Anal short, originating opposite end of depressed dorsal. Origin of ventrals opposite first 

 dorsal ray. Pharyngeal bones slender ; teeth acutely uncinate-raptatory, without masti- 

 catory surface, 1.4 — 4.0. 



I am not aware that any genus of Cyprinidue exists in the Old World which possesses 

 the cavernous structure above mentioned. Traces of it maybe observed on the interoper- 

 culum in certain genera, e. y., Hypsilepis. 



The tooth series is situated entirely below opposite the alar angle of the pharyngeal 

 bones, as in Exoglossum ; in other genera the angle falls opposite the middle of the scries. 

 The length of the alimentary canal is less than that of head and body, and the natatory 

 bladder extends throughout the whole length of the abdominal cavity. 



ERICYMBA IUJCJCATA, Cope, loc. cit., Supr. 



The suboperculum is small; operculum height to breadth as one and one-half to one. 

 Head broad, muzzle obtusely rounded. Cantlius of mouth opposite nares. Length of bead 

 contained three and live-sixths times to origin of caudal; greatest dopth (at dorsal) nearly 

 five times in the same. Caudal peduncle elongate, not constricted. Eye large, contained 

 a little more than three times in length of head, a. little more than frontal width. Origin of 

 dorsal a little in advance of the point midway between end of muzzle and origin of caudal, its anterior ray equals 

 half the distance from its base to anterior nostril. Caudal furcate one-half its length. Ventrals barely reaching 

 vent; pectorals attaining ventrals. Scales jj oil ; exposed portion with very numerous and delicate radii and con- 

 centric lines, not visible to the naked eye. A narrow space from vent to opposite middle of pectorals scaleless. 

 fins, 1)1. S. C. + 17 + . A. 1. 8. V. S. P. 12. Lateral line nearly straight. Along and above it is a lateral band 

 of brown punctulations ; general color above yellowish olive, the edges of the scales dark-shaded, and a narrow 

 brown vertebral line from nape to tail. Below lateral line silvery. Dorsal and caudal fins rosy. Length of a 

 hall-grown specimen, from muzzle to opercular edge 7 1. ; to dorsal lin 13 1. ; to end of appressed anal 1 in. 9 1. ; 

 to origin of caudal 2 in. 2 1.; to end of caudal 2 in. 8 1. 



This species was originally known only from the Kiskiminitas, but Dr. Stimpson lias 

 taken it in abundance in the Muskingum, and William P. Clark, in the White River, 

 Indiana, thus indicating an extensive distribution. 



VOL. XIII.-— I fi 



