212 Cockerell — On the Genus Notemigonus. 



BaUerus Heckel, 1848, is probably a dit-tinct genus. The scales of 

 Ballerus haUerus or Abramis ballerus, from the Danube, have the general 

 form, and the extremely fine circuli, of Abramis brama, but the radii, 

 which are all apical, are reduced to from four to six, and these are 

 mostly broken and incomplete. This is an independent development, 

 not at all approaching Notemigonus. 



Abramis vimba (L. ) (Olmiitz, Jeitteles ; Brit. Mus. ) typifies another 

 rather distinct group, the scales shaped nearly as in A. brama (L. ), the 

 nuclear area central and broadly granular, the circuli next to the nuclear 

 area not dense, apical radii only about 12, some evident but feeble basal 

 radii. This is entirely diff"erent from BaUerus in the nuclear region, 

 which in the latter has very fine circuli practically to the middle with no 

 granular area. 



Abramis sopa Pall., from Astrachan, falls in the same group as A. 

 vimba on scale-characters, but the circuli are much closer, and there are 

 no basal radii. 



Abramis blicca Bl. (genus Blicca Heckel) may also be referred to the 

 same group, but the nuclear area is very broadly granular, the fine granu- 

 lations extending even among the circuli at the sides. The apical radii, 

 about 13, are more or less incomplete; there are two or three imperfect 

 basal radii. 



Abramis elongatus kg. (Wiirm See, Bavaria, Prof. v. Siebold; Brit. 

 Mus. ) has scales which are quite distinctive ; the nuclear area very dis- 

 tinctly basad of the middle (herein approaching Notemigonus), without 

 a granular area; the circuli rather less dense than in most species; the 

 apical radii five or six, with one or two others rudimentary; basal radii 

 represented by feeble rudiments. There is a certain resemblance to 

 BaUerus. 



Abrama buggenhagi Bloch (canal at Slough, Ling and Ladbrook; Brit. 

 Mus.) is referable to the subgenus Abramidopsis Sieb. The scales show 

 a central nuclear area, without granulations; basal radii evident and 

 rather numerous ; apical radii a{)pareutly only three or four, but on close 

 inspection numerous jjarallel rudimentary radii or furrows are visible, 

 showing some resemblance to the structure found in ^4. brama. Abramis 

 buggenhagi is considered to be a hybrid between Abramis brama and 

 Leuciscus rutilus. Its scale may fairly be said to resem])le a "composite 

 portrait" of the scales of these two fishes, with, however, a considerably 

 greater resemblance to that of L. rutilus than that of A. brama. The 

 basal part of the scale is quite in the manner of L. rutilus. In Mendelian 

 terms, one might say L. rutilus dominant, but the dominance not quite 

 complete. 



The classification of the fishes under discussion will then be as follows : 



(A) European fishes with dense circuli, and nuclear area nearly always 

 central or nearly so. 



Abramis Cuvier. 



(a) Abramis s. str. A. brama L. 



(b) Abramidopsis Sieb. A. buggenhagi Bloch. 



