374 



SYNOrSIS OF THE CYPRINIDiE OF PENNSYLVANIA. 



In the brooding season minute asperities cover the dorsal line in front of the dorsal fin, and appear on the upper 

 and lower aspects of the head. The latter are most abundant on the preorbital region ; on frontal region sparse 

 minute. Rows on the superciliary and lower edge of suborbital regions, and two on each ramus mandibuli. 

 Length of head four times in length to base caudal, and less than depth of body. Scales of anterior dorsal region 

 much smaller than those of the lateral ; latter with exposed surfaces very narrow, and crested with minute tuber- 

 cles in the breeding season. 



Color, dusky above, the sides and belly silvery, without band; below crimson in spring. A largo black spot at 

 base of dorsal fin. Length extends to four inches, according to Prof. Kirtland; of a specimen in Museum Acad- 

 emy, from Lansing, Michigan, 2 inches to origin caudal; 12.5 lines to origin dorsal; 6 lines to opercular margin; 

 depth 7 lines. 



I introduce this species on the authority of Prof. Kirtland, who states that it is abundant 

 in all Western streams, and that it ascends rapids in shoals in spring, for the purpose of 

 depositing its eggs. 



CLINOSTOMUS, Glrard. 



Proc. Acad., Phila., 1856, 211. 



As originally defined, the group bearing this name was not distinguishable from Squalius 

 of Europe, with which I accordingly connected it. The elimination of some of Girard's 

 characters leaves, however, a natural genus for which his name may be retained. It is 

 represented in Pennsylvania by four species, one of which has not yet fallen under my 

 observation. They are the most brilliantly-colored Cyprinida; of this or any other country. 



The characters of the genus as here understood, have been already given. It differs 

 from Phoxinus principally in the large oblique mouth and prominent mandible, and the 

 complete lateral line. The scales exhibit strong concentric ridges, and the lateral line is 

 often much decurved, as in Stilbe. 



The Phoxinus laavis is common in every stream in Middle Europe, much as Argyreus 

 atronasus is here. It is ornamented with brilliant colors during spring. The present spe- 

 cies are much less abundant, and are distinguished by the much larger size of their scales. 



A nearer ally of the European fish exists in our country, however, than has been sus- 

 pected, in a species of the same genus. This, our Phoxinus neogacus, has not been 

 detected in Pennsylvania, but was procured during the zoological survey of Michigan, on 

 the ichthyology of which a report was published in the Proceedings of the Academy 

 for 1864. Its slightly oblique mouth indicates affinity with Clinostomus. As these 

 species bear considerable external resemblance to those of Chrosomus, they may be super- 

 ficially compared thus : 



Clinostomus margarita. Scales largest, head shortest, no dark lateral band. 



