^^~ 



36 BULLETIN OF THE BUREAU OF FISHERIES. 



Salmonids. 



Coregonus ■williamsoni Gitaid; C. williamsoni, p. 463. 



Salmo henshau'i Gill and Jordan; S. clarkii heiusham (2819), p. 493; S. clarkii iahoensis, p. 2870. 



Salmo aquilarum new species. 



Salmo regalis Snyder. 



Salmo smaragdus, new species. 



i " Coitus beldingi Eigenmann; C. beldingii, p. 1958. 



Of these, Chasmistes cujus is confined to Pyramid and Winnemucca Lakes, from 

 which an annual spawning migration is made in the lower course of Truckee River. 

 Richards onius microdon is known from a few specimens caught with baited hook in 

 Lake Tahoe. Leucidius pectinifer is lacustrine, breeding in the lakes and apparently 

 never entering the rivers. Salmo aquilarum is a rainbow trout, which presumably 

 entered Eagle Lake after the latter was detached from direct Lahontan drainage 

 5. regalis and 5. smaragdus are lacustrine. Their breeding habits are not known. The 

 other species are generally distributed throughout the system. 



In the presence of our limited knowledge of western fresh-water fishes it is con- 

 fessed that an attempted discussion of the relationships of the Lahontan fauna is 

 somewhat premature. A better acquaintance with the species in the headwaters of 

 the Sacramento Valley streams and with those in the upper Columbia and the Snake 

 Rivers is desirable, and something more should be known of the Bonneville fishes than 

 has been recorded in their descriptions. However, it appears probable that, unless the 

 purport of facts now at hand is wrongly interpreted, certain inferences may be drawn 

 which will not be greatly altered by future investigation. 



The position of the system being completely insular it may at once be assumed 

 that the affinities of the Lahontan fishes are to be sought among the faunas of con- 

 tiguous systems, and the assumption is well founded, as will be seen. When the rela- 

 tionships of a Lahontan species are apparent, they invariably are found to be with a 

 form indigenous to a neighboring basin. 



The Colorado River fauna does not appear to be directly represented in the Lahon- 

 tan system. Among the Sacramento River fishes there are fine and coarse scaled 

 catostomids similar to those of the Lahontan, a lake chub, Sipliaieles formosus, much like 

 5. ohesus, while the Sacramento and Lahontan species of Agosia and Coitus are distin- 

 guished with difficulty. The same may also be said of similar species found in the 

 Klamath and Columbia Rivers, the near-related forms being enumerated in the fol- 

 lowing list: 



Lahontan: C. iahoensis, C. arenarius, S. obesus, A. robusia, C. beldingi. 

 Sacramento: C. microps, C. occidenialis , S.formostis, A. carringtoni, C. gulosus. 

 Klamath: C. rimiculus, C. snyderi, S. bicolor, A. klamathensis , C. klamathensis . 

 Columbia: C. catosiomus, C. macrocheilus, S, columbiamis, A. carringioni, C. gulosus. 



However, it is when the Oregon Lake system is approached that we find species 

 that are most closely related to those of the Lahontan, for an .Agosia, a Siphateles, 

 and a Catosiomus are here which scarcely differ from representative forms found in 

 the latter system. It therefore appears probable that certain species of the Lahontan 

 fauna are most closely allied to those of the Oregon Lake system and through these 

 to similar forms in the Sacramento, Klamath, and Columbia. The affinities of one 

 Lahontan species, Chasmistes cujus, may be traced to Klamath Lake (fossils of the 



