360 



SYNOPSIS OF THE CYPRINID7E OF PENNSYLVANIA. 



percle and ccratohyal, with the basihyal and strong elongate urohyal, defend the lower 

 surface of the head effectually. 



This structure is obviously associated with the habits of the animal. The stomach 

 usually contains abundant remains of Physse, Pisidia, and other small mollusca, which 

 form its food. The shovel-like mandible would appear to be adapted for removing these 

 creatures from their hold on the rocks and bottom, while the great strength of the pharyn- 

 geal walls and muscles enables the fish to crush the shells before mastication with the 

 pharyngeal teeth. 

 - Besides the below-mentioned, Girard describes a species from Texas. 



EXOGLOSSUM MAXILLINGUA, Leseur. 



Cyprinus rnaxillingua, Leseur, Proc. Acad. Nat. Sciences, Phila., 

 1817, 85. Exoglossum, do., Flaldeman, Rupp, Hist. Lancaster Co , Pa., 

 1844, 474, Agass., 1. c, Girard, I. c. 



Eye on the frontal plane, opening longitudinally oval, longest diameter 4 J times in head, one 

 and a half times in muzzle. A bony prominence at angle of proopercle and base of mandible ; latter withdrawn into 

 mouth when closed. Mouth slightly oblique, end maxilla not attaining line of orbit. Operculum higher than 

 broad, convex below; the sub-opcrculum sickle-shaped, incurved; top of cranium broad, piano between nares ; 

 muzzle suddenly descending; interorbital breadth equal from end of mandible to margin of prcoperelc; scales, ex- 

 posed portion higher than wide, radial grooves very numerous, and with the concentric ridges strong; 10-49-5; 

 lateral line deflcxed in front, median behind middle of dorsal fin. Head five times in total length or four and a 

 quarter to base caudal ; greatest depth five times to base of caudal. Caudal peduncle, depth If of greatest length. 

 Back broad anteriorly, compressed at base of dorsal fin. Pectoral fin | length to ventrals; latter to vent; basis of 

 anal less than that of dorsal; height of anal ith more than basis of dorsal, equal height of dorsal; outlines of both 

 straight. Bmargination of caudal, one-third its length. 



Length of a fully grown individual 5.75 inches; end muzzle to first dorsal ray 2.57 ; same to origin caudal 

 2.44; first anal to same point 1.5; breadth between pracoporcula below .75. Color olivaceous, smoky above; a 

 blackish band from pectoral fin to superior extremity of gill opening. 



This fish is abundant in all the tributaries of the Susquehanna which have been exam- 

 ined, and is not known from other waters. In its movements it is sluggish ; it keeps near 

 the bottom in pools and channels of our clear rocky streams, not preferring rapids. It 

 takes the hook very readily. 



EllICYMBA, Cope. 

 Proceedings Acad. Nat. Sciences, Phila., 1865, 87. 

 This form appears to be related in structure to allied genera of the Cyprinidse, as 



