84 Annals of the Carnegie Museum. 



Thymallus nikolskyi var. ongudajensis Kaschchenko, ibid., 134 (Altai, Urusul 



River). 

 Thymallus sellalus Kaschchenko, ibid., 135, tab. II, fig. 6 (Altai, Tengo River, 



Urusul River). 



Fifty-seven specimens. 



Among these great variation was shown, leaving it highly probable 

 that there is but one species of grayling in the basin of Lake Baikal, 

 and that the grayling of the Amur is not distinct from it. It seems 

 necessary to unite with Thymallus arcticus Pallas the forms called T. 

 ardicus baicalensis Dybowski, T. pallasi Vallenciennes. and (probably) 

 T. grubei Dybowski also. The two former are said to be distinguished 

 from the two latter by the dorsal length being more than 22.5 per cent 

 of the body length, and the distance of the snout from the dorsal not less 

 than 34 per cent, the dorsal length being not less than 23.5 per cent and 

 the dorsal from the snout not more than 32.5 per cent in T. pallasi and 

 T. grubei. These distinctions are given by Dr. Leo Berg in his paper 

 "Provisional Notes on the Eurasian Salmon," published in the Annuaire of 

 the Zoological Museum of the St. Petersburg Academy of Sciences, T. XII, 

 1907. 



In the present collection there is shown not only every variation 

 between these nominal species, but there is little correlation between the 

 two sets of measurements. Some specimens show both the shorter dorsal 

 fin and the shorter distance from the snout to the dorsal. The number of 

 scales is held to separate T. baicalensis horn T. arcticus, baicalensisha.vmg 

 more than 90 scales in the lateral line and arcticus less than 90. Such a 

 division is evidently entirely artificial, as shown by the accompanying 

 table. Thymallus grubei of the Amur is probably synonymous with 

 Thymallus arcticus, but there are some grounds for believing it a distinct 

 species. None of our specimens have so small a number of scales (83-87 

 in the lateral line) as is ascribed bj^ Berg to Thymallus grubei, and the 

 species is from a different water basin. The jaws are said to be subequal, 

 and the maxillary extending farther back than in Thymallus arcticus. 



Measurements were made of all our specimens (57), from 133 mm. to 

 325 mm. in length. In the attached table only those above 210 mm. in 

 length are given. The remainder fully conform to these measurements. 

 No other distinguishing characters set off the specimens representing 

 the extremes of this species. 



The male specimens are much darker in color than the females, the 

 spots in both becoming obscure with age. The dorsal fin is much higher 



