790 



SCANDINAVIAN FISIIKS. 



SrBFAMii.v A BR AMI DIN J:. 



Dorsal _tin much slmrtrr tliax flic <nial, tin- base af the former medsiiriuf/ as a rule less tluni ^,,3" of lliaf of the 

 latter, nhicli is more than Id % of the lein/fh of the ImhIi/. Leiii/th of the head less than half the distaiiee he- 

 ttveen the dorsal fn and the fiji of the siioaf. No spinous ray in the dorsal or the anal fn. Ventral marf/iv be- 

 tween the ventral fins and the anal aperture sliarp, hut generally naked {not covered u'ith eurved scales) in the 

 median line. Mouth irithout harhels. Length of the lower jaw as a rule less than 47' % of that of the base of the 

 anal fin. Pharyngeal cartilage oral or cllijjtical, with the anterior {npper) extremity more or less ohtitscly jminted. 



These chiirMcters are accompanied by the well- 

 kii(j\\n Abraiuidine form, a deep and compressed body 

 with strongly compressed or even sharp margins, along 

 which the scales are shed at certain parts of the me- 

 dian line, the two ontermost rows of scales being thns 

 juxtaposed edge to edge, or leaving the skin at these 

 parts naked. This is always the case, even in Albiirnus 

 and, at least jxirtially, in Spirlinus, along the ventral 

 margin between the ventral tins and the anal aperture; 

 and in the true Breams the dei nidation extends, tliough 

 with varjdng distinctness, to the anterior part of the 

 dorsal margin behind the occiput. 



It was not without reason tliat Nils^on proj)Osed 

 to unite all the Scandinavian Abramidines into one 

 genus. Great as the difference may appear between a 

 Bleak and a Bream, we find intermediate forms be- 

 tween them composing an almost unbroken series. A 

 species found in Denmark and further south, Spirlinus 

 hipunctatus, has also been referred by some, for ex- 

 ample by GuNTHEK, to the genus Abramis, by others, for 

 example Heckel and Siebold, to Allniriiiis. The near 

 relationship of this subfamily to the preceding one, a re- 

 lationship which in its intermediate forms and hybrids 

 defies every attempt by fixed characters to define the li- 

 mits between these two groups, has caused a like diver- 

 sity of opinion, the Bleak being referred by Aijassiz, 

 Kroyer, Nilsson, and Lilljeborg to the same genus as 

 the Asp. If the systematic classification of forms so 



closely allied is to be based on natural grounds, we are 

 compelled for the sake of consistency to employ as ge- 

 neric characters relations which elsewhere seem to be of 

 comparatively little weight. Hence Fatio established his 

 new genus Spirlinus, and for the same reason we are 

 obliged to divide the germs Abramis, with a view to 

 obtaining an expression for the points of resemblance 

 between the 'ZiVrthe' and preceding forms and the 

 respects in which it differs widely from the true 

 Breams. 



The genera belonging to the Scandinavian fauna 

 may be distinguished as follows: 



I: Length of the head more than ' ., of 



the distance between the dorsal tin and 



the ti]) of the snout. 



A: Base of the anal fin less than ' - of 



the length of the body and shorter 



than the head. 



u: Lower jaw most prominent. Pec- 

 toral fins longer than the longest 



ray in the dorsal fin _ Genus Alburnus. 



Ir. Jaws about equally prominent. 



Pectoral fins shorter than the 



longest ray in the dorsal fin ... Genus i<]iirliiuis. 



c: Tip of the snout most prominent. 



Pectoral fins shorter than the 



longest ray in the dorsal fin ... Genus T^eiicahramis. 

 B: Base of the anal fin more than ',5 

 of the length of the body and as 



a rule longer than'' the head.. Genus Ahramu. 



II: Length of the head less than '3 of the 

 distance between the dorsal fin and the 

 tip of the snout Genus I'eleciis. 



" Invariably less than 72 % in all the specimens nie.isured liy us. 



'' In White Bream and young Bream exceptionally equal in length to the he.id. 



