SYNOPSIS OF THE OYPUTNIDyE OF PENNSYLVANIA. 



393 



Pharyngeal teeth slightly hooked. Frontal region flat, its breadth more than half length of top of head; out- 

 line of the latter broadly truncate. Profile truncate. Eye contained four times in length of head, once between 

 its anterior border and the end of the muzzle, a little more than half frontal width. Length of head entering 

 four and one-half times in length to base of caudal fin, and equal greatest depth of body. 



Scales 6 — 44-5 — 4, exposed portions higher than long. Dorsal fin longer than high, highest anteriorly, supe- 

 rior outline straight, 1. 8; caudal not deeply forked, 19; anal free border longer than anterior, 1. 7; ventrals not 

 reaching vent, 1 — 8. Total length three inches. Length from base of caudal to anterior base of dorsal greater 

 than from latter point to end of muzzle. 



General color reddish, cheeks silvery. A darker shade along lateral line, and a black spot at the base of the 

 tail. 



In general features this species is allied to the Pimcphales, the excessively broad obtuse 

 muzzle, with tubercles in front, and small inferior mouth, giving it much the same physi- 

 ognomy. The arrangement of the former is as follows : 



There are two rows crossing the front of the muzzle ; the inferior of six, of two on 

 each side on the premaxillary border, and an outer near the eye ; the superior of five, one 

 on the middle line. A third row of four is on the border of the superior plane, one behind 

 each pair of nares, and one on each side the middle line of the muzzle. 



CAMPOSTOMA, Agassiz. 

 Amer. Journ. Sci. Arts, 1855. Girard, Proc. A. N. S. Phila., 1856, 170. 



Species of this genus have as yet been only found in the tributaries of the Ohio, in our 

 State. The known species are from the waters flowing into the Lakes, the Mississippi, 

 and the Gulf. While it represents in our waters the Chondrostoma of Europe, as pointed 

 out by Agassiz, the arrangement of the abdominal organs is now found to be so peculiar 

 as to separate it more widely from the latter than has been hitherto accepted. This has 

 been indicated above in the diagnosis of the tribe Mesocysti. Hybognathus indeed coin- 

 cides more nearly with Chondrostoma, though it lacks the acute labial sheaths, but the 

 palueotropical genus Gymnostomus, Heckel, affords an intermediate form of mouth. In 



vol.. XIII.- 



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