BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND 26. AFD. IV. N:0 8. 17 



All these measurements lie witliin the limits of variation 

 of the Swedish Scardinhis er ytJiroplit halmus with tlie only 

 exception that the dorsal fin has a still more posterior posi- 

 tion in the specimen from the Volga delta. This is plainly 

 seen when comparing the percentages expressing the distance 

 between the snout and the dorsal fin. In the Volga specimen 

 this is, as stated above, 63,3, but in Sweden it is said to vary 

 between 52 and 56, according to Smitt (1. c). This is a con- 

 siderable difference and the more important as the position 

 of the dorsal fin gives one of the fundamental characters to 

 the genus Scardinhts. If this characteristic is constant in 

 the Scardinius from the Volga delta it would thus indicate 

 a more specialised form than in the Scandinavian one or a 

 form more advanced in the direction of development through 

 which Scardinius is differentiated from its allies. 



I did not observe the »krasnoperka» but in the Volga 

 delta. 



Aspius aspius (Lin.). 



The sheréch) of the Volga delta. I only saw small 

 specimens of this fish in the river and do not remember 

 having seen it caught in the sea. I did not see any speci- 

 mens in Transcaucasia either, but heard there about a fish 

 called »shaschan», or something like that, which was said to 

 be identical with the »sheresch». This was perhaps Varpa- 

 CHOVSKij's A. transcaucasicus. It should ascend the Trans- 

 caucasian rivers at the same time as the jsudok», namely in 

 the latter part of February and in March, but it was a com- 

 mon belief that these two species would not simultaneously 

 enter the same river in great numbers, »but if one selected 

 one of the northern rivers, the other would choose another 

 more southern, and the contrar}^». 



Alburnus chalcoides Guldenstaedt. 



Total length 



Length of head in % of tot. length 



Height of body j » > ». > 



Distance from snout to dorsal fin > > » > > 



> » 1 j> anal » j > » » » 



» I » k ventral i > > > > > 



267 285 285 



20.5 20,0 19,6 

 20,2 19,3 19,6 

 47,9 49,8 48,7 



63.6 60,5 61,7 

 44,5 41,4 41,7 



