Jordan and F.TfDiiaini. — Fishes of ^Yor//i .■1»ierira. 229 



usually 2, 5-5, 2 in the European type ; hooked, with rather narrow grind- 

 ing surface or none. Anal basis short or more or less elongate. Dorsal fin 

 posterior, usually behind ventrals. Intestinal canal short. Size generally 

 large, some species very small. A very large group, one of the largest 

 current genera in ichthyology, represented by numerous species in the 

 rivers of Europe, Asia, and North America. Most of our species have been 

 poorly defined. As the species are extremely variable iu form, the number 

 of nominal ones has been very greatly multiplied. Much larger series of 

 each form are necessary before the species can be properly discriminated. 

 Individual irregularities in dentition are common in this genus. 



The typical species of the genus, Lnicisciis leiiciscus, is the common Dace 

 or Vandoise of Europe, and differs greatly from any of the American 

 forms. The presence of various intermediate species, however, makes 

 it impossible for us to draw any satisfactory line between the Dace 

 (Leuciscus) on the one hand, and such extreme forms as the long-mouthed 

 minnows {Clinostomus) on the other. 



In the subgenus Leuciscus the pharyngeal teeth are 2, 5-5, 2, rarely vary- 

 ing to 3, 5-6, 2, and the scales are rather large (about 50 in lateral line), 

 closely imbricated and along the sides distinctly silvery. The anal fin is 

 also long, of 11 to 12 rays, and the Jateral line complete. The genus 

 Squalius, as understood by us, is strictly synonymous with Leuciscus. In 

 southeastern Europe and western Asia Leuciscus is reiilaced by the sub- 

 genus Tdestes, which has the teeth 2, .5-4, 2, the scales much smaller (70 to 

 80), and not silvery, the anal fin still remaining long, and the lateral line 

 complete. The American species ca.led Tigoma and C'hconda are very close 

 to Telestes, from which they differ only in the less closely imbricated 

 scales, most of them, but not all, having the short anal fin generally char- 

 acteristic of American Ci/j^-inidce. Tigoma can not be generically separated 

 from Telestes, though it may be a question whether either should be united 

 to Leiiciscus. Cheonda difters from Tigoma iu having the long anal fin of 

 Leuciscus. liicliardsouius is simply an extreme form of Cheonda. Sihoma is 

 founded on a Tigoma with very deep body and the scales less loosely imbri- 

 cated than usual. CVniosfomus is a peculiar group of small, fine-scaled 

 minnows, with the gape of the mouth larger than in any other CUjpriuida'- 

 whatever. The relationship of the species to those called Bichardsonius is, 

 however, very close. The type of Phoxinus differs from Leuciscus in its 

 incomplete lateral line and very small scales. In the latter resjiect the 

 subgenus ife/»i7;'e»n'fl forms a complete transition to iewciscHS, and some of 

 its species (as margarita) have the lateral line scarcely defective. Con- 

 sidering all the known species, Phoxiuus can not be separated from 

 Leuciscus. It may even be necessary to merge L'utilus and its American rep- 

 resentatives, Leuctis and Mylolencus, in the same great group. (Leuciscus, 

 old name of the Dace, from AevKog, white.) 



I. Lateral line complete iu the adiilt. 

 o. Mouth moderate, terminal, or subinferior, the lower jaw incUuled, or scarcely projecting; 

 teeth normally 2, 4-5, 2 ; scales rather email. 

 5. Anal basis short, its rays 7 or S, rarely 'J • fins low ; males not brilliantly colored. 

 SiBOMA, (a coined name without meaning*): 



*Liko many other of Girard's Rpncric names ; drawn ostensibly from "words taken from the 

 North Aniciican Indians as more euphonic than any I might have framed from the Greek." 



