VENDACE. 
893 
most of the forms ascend from the Arctic Ocean, and 
in the great lakes of North America. But even in Scan- 
dinavia it ranks among the fishes most important from 
an economical point of view. The number of the spe- 
cies it is as yet impossible to determine, for the vari- 
ability of the forms is as great here as among the 
Salmons, and has given rise to the establishment of 
numerous, merely nominal species. 
The name of Coregonus was coined by Artedi" 
and has reference to the anterior angle of the pupil. 
THE VENDACE ( SAV. SIKLOJAN OR RABBOXEN). 
COREGONUS ALRULA. 
Plate XLII, fig. 2. 
Lower jaw projecting beyond the shadow (sharp) tip of the snout, at which the breadth (height) of the intermaxil- 
laries is less them 2 / 5 of the breadth of the snout across the articular knobs of the maxillaries. Length of the base 
of the anal fin less than 14 % of the length of the body. Least depth of the tail less than 8 % of the length of 
the body or 45 % of the length of the head, but more than 47' % of the length of the base of the anal fin. Ver- 
tical diameter of the eyes more than 71 % of the breadth of the interorbital space, ivhich is less than 30 % of 
the length of the head and usually less than the length of the upper jaw, which is more than 1 / 3 of the length 
of the head or V 5 of that of the head reduced. 
a: True Sikloja (var. cdbula): distance between the dorsal fin and the tip of the snout usually more than 42 % 
of the length of the body, and the postabdominal length less than 02 % of that distance. Gill-rakers on the 
first branchial arch more than 40. Least depth of the tail at most 71 % of the length of the base of the 
anal fin. Length of the head, even in full-grown specimens, as a rule more than 19 %, and of the head 
reduced more than 15 %, of that of the body. 
b: Sikvimma (var. vimba): as above, but: length of the head as a rule less than 19 %, and of the head reduced 
less than 15 %, of that of the body. 
Fig. 22.3. Coregonus vimba, 10 n of the natural size, o 71 , from Stora Nyckelviken (Lilia Vartan) in the island-belt of Stockholm. 
Caught on the 12th Aug., 187 9. 
Philos. Iehthyol., p. 72. xo qyj, pupil, and yiovla, angle. 
