372 T. D. A. COCKERfcLL. 



teristic distinction between New World and Old World Cyprin- 

 ids, although some of the Old-World genera have widely-spaced 

 circuli. The two Japanese species, as one might expect, are 

 rather intermediate between the European and American. They 

 probably should constitute a new subgenus or genus. Leuciscus 

 illyricus (Fig. 7) has widely spaced apical circuli, and therein 

 departs in the direction of the Japanese and American fishes. 



The Characinidse are a large family of freshwater fishes oc- 

 curring in the Ethiopian and Neotropical regions, but not else- 

 where, with the exception of a few which enter the Palsearctic 

 in the Nile Valley and the Nearctic in southern North America. 

 This curious distribution has naturally aroused interest among 

 naturalists, and while it is probable that America was their original 

 home, it is a question whether they reached Africa across what 

 is now the Atlantic, or once inhabited the north and passed south- 

 ward into the Ethiopian area. I should think the latter sup- 

 position more probable, but for the fact that as yet we have no 

 trace of fossil characinids outside of their present area. The 

 characinids belong to the same general group as the cyprinids, 

 but are unquestionably more primitive, in spite of the fact that 

 many of their members are exceedingly specialized in certain 

 particulars. Among the African characinids is a group, the 

 Alestini, having a very characteristic type of scale. 1 This, 

 which I call the alestiform scale, is more or less hemispherical 

 in outline, cycloid as to the margin, with a few very strong radii. 

 It seems to be an old type, because we find it nearly repeated in 

 certain of the relatively primitive families, as for instance the 

 Phractolsemidse (Phractolcemus ansorgii, Fig. ija), a rare type from 

 the Niger and Congo rivers. The Phractolcemus scale, however, 

 is incipiently ctenoid. A different scale, yet of the general alesti- 

 form type, is found in Pantodon buchholzi (Fig. 18), another rare 

 and isolated genus from the Niger and the Congo. On this fish 

 the circuli have a peculiar and very characteristic bead-like 

 appearance. Passing to the more specialized cyprinids, we find 

 the alestiform scale not uncommon, and a good example from an 

 Asiatic fish (Barbus mahecola, Fig. 19) is given. It will also be 

 noted that Leuciscus nitilus of Europe (Fig. 10) has much the 



1 See Smiths. Misc. Coll., Vol. 56, No. i, plate i, figs. 4, 5, 6. 



