194 



NORTHERN ZOOLOGY. 



grayling, the scales are more nearly smooth on the edge tahn in the American fish, and the 

 teeth of their bases are smaller and more numerous, being four or more. 



Dimensions. 





Back's 



En; 



;lish 





Grayling. 



Gra; 



ling. 





In. lin. 



In. 



lin. 



Length from lip of snout * to tip of caudal 



17 6 



17 



6 



„ „ end of caudal rays of ditto . 





16 6 



16 



3 



,, ,, end of scales on central rays 





15 6 



15 



6 



„ „ anus 





11 



11 



3 



„ „ ventrals 







7 3£ 



7 



6 



„ „ dorsal 



. 





4 11 



5 



5 



,, „ edge of gill-cover 







2 5 



2 



9 



„ „ nape . . 



. 





1 10 



2 



2 



„ „ edge of orbit 







4J 







8 



„ „ nostrils . 







3 







7 



Breadth between articulations of labials 







8i 







8 



,, of occiput .... 







1 2 



1 



2 









8| 







n 



„ lower jaw .... 







2 4 



2 



4 



„ attachment of dorsal . 







3 11 



3 



11 



„ its penultimate or longest ray . 



. 





4 



2 



4 



„ adipose fin .... 







9i 







8 



„ pectorals .... 







2 6 



2 



3 









2 2 



2 



3 



„ ventral appendages 







7 







7 



,, attachment of anal 







1 4 



1 



5 



„ its longest rays 







1 8 



1 



8 



„ lobes of caudal .... 







2 8i 



2 



7 



,, its central rays beyond the scales 



. 





1 







9 



Depth of caudal fork ..... 





10 



1 



2 



[74.] 2. Salmo (Thymallus) thymalloides. (Richardson.) Lesser 



Grayling. 



Coregonus thymalloides f. Richardson, Frank/. Journ., p. 714. 



A much smaller grayling was taken in Winter River along with Back's gray- 

 ling, from which it differed in its tints of colour, brighter scales, and in the shape 

 and size of its dorsal fin. At the time, I thought these variations sufficient to 

 characterise it as a distinct species, but having since ascertained that the dorsal fin 

 varies greatly in size, and even in shape, in the European graylings of different 



* Or articulation of labials, and not including the intermaxillaries, which project beyond the snout when the mouth 

 opens. 



f Thymalloides is objectionable as a specific name in the sub-genus Thymallus, but I did not consider necessary to alter 

 it, as the species is a doubtful one. 



