LEUCISCUS RODENS. 



163 



that most writers have followed the example of Von Siebold in uniting them 

 without an attempt at defining their geographical distribution. 



Heckel and Kiier endeavoured to distinguish several of these varieties 

 as species. Thus the Lenciscus chalylaus has the head directed rather more 

 downward so as to give a relatively convex profile to the back, and was re- 



Fig. 86. HEADS OF LEUCISCUS VULGAKIS I A, OF TYPE J , OF VAU. ROUEXS. 



garded by them as peculiar to the little river Kamp in Lower Austria, where 

 it frequents deep water (see FRONTISPIECE). 



Another variety, Leuciscus rodens, is remarkable for its elongated form and 

 rather short head (Fig. 86, B) . The depth of the body exceeds the length of the 

 head, and its thickness is more than half its height. The nose is thick and 



Fig. 87. LEUCISCUS VULGARIS, VAR. ROSTRATUS (HECKEL). 



arched. The scales are rather small, the largest being only half the diameter of 

 the eye. Below the lateral line there is a clear silvery or golden longitudinal 

 band. All the fins are transparent, and the back is greenish-blue. At 

 spawning-time the males develop black pigment spots, which afterwards vanish. 

 This form is found in Lake Constance, and is probably the fish found in the 

 Neckar, in which Giinther describes a similar development of pigment at the 

 spawning period. Fatio mentions the association with these spots with white 



