VI. NOTES ON A COLLECTION OF FISHES MADE BY 

 JAMES FRANCIS ABBOTT AT IRKUTSK, SIBERIA. 



By David Starr Jordan and William Francis Thompson. 



In the >car 1904 a collection of fishes was made by Mr. James Francis 

 Abbott, then Professor in the Japanese Naval Academy at Etajima, 

 at Irkutsk in Siberia, in the Rivers Angara and Irkutsk, the outlets of 

 Lake Baikal. 



In the collection are eleven species, none of them new, but some of 

 special interest. We present here an annotated list. The drawings are 

 by William Sackston Atkinson. The specimens in question are in the 

 Museum of Stanford University, in the Carnegie Museum, and in the 

 I'nited States National Museum. 



Family SALMONID.E. 



I. Brachymystax lenok (Pallas). (Plate XX.) 



Salmo lenok Pallas, Reise, II, Appendix, 1776, 716 (mountain torrents of the Altai). 

 Salmo coregonoides Pallas, Zoogr. Ross. -As., Ill, 1811, 362 (Rivers of Irtes, 



Yenesei, Angara, Seleuka, Lena, Witem, Kovyma; Lake Baikal). 

 Brachymystax coregonoides Gunther, Cat., VI, 1866, 163. 



Ten specimens, 14 to 350 mm. in length. 



Head 4^ in body without caudal; depth 5; eye 6 in head; 2 in 

 interorbital space. 1 3^ in snout. B. 10-12. D. 12 or 13 (developed rays). 

 A. 10 or II. V. 10 or 11. P. 14 to 17. Pyloric caeca about 90. Gill- 

 rakers 23 to 25. Scales 34-146 to 156-21. 



Body somewhat compressed, its breadth about one-half its depth, stout, 

 convex on the ventral side and on the dorsal anterior third. Head some- 

 what conical, arched dorsally from the snout; snout broad, rounded, and 

 of moderate length; lower jaw, measuring from the articulation with the 

 quadrate, one-ninth shorter than the upper; maxillaries broad, 2 to 2j^ 

 in their length, extending to below the anterior third of the eye; lower 

 limb of preoperculum long. Dentition is rather feeble, but complete, 

 the teeth on the tongue, in two rows of 4 to 5 each, stronger than the 

 remainder; vomer with teeth anteriorly only; gill rakers numerous, mod- 

 erately long and stiff; dorsal fin low, truncate, the last ray one-half length 

 of first, its base 7^2 to 8 in body length ; adipose fin large, its base opposite 



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