78 BULLETIN OF THE BUREAU OF FISHERIES. 
between certain elements of the aggregate fish fauna of the Sacramento, Klamath, 
and Columbia rivers not hitherto known. A simple explanation for these inter- 
relationships offers itself when some attention is given to the geography and geology 
of the region. The close proximity of many tributaries of the three systems, which 
appears to have been even more pronounced in a past geological period, has probably 
made possible an intermingling of their waters, thus permitting the passage of indi- 
viduals of certain species from one basin to another, where their descendants, being 
able to maintain themselves, have in most cases become sufficiently differentiated 
to be recognized as distinct species. 
TaBLe SHowrne DisrrRiBuTION oF THE FisH Fauna. 
Sacramento River system. 
Goose Lake Basin. Sacramento River Basin. 
| 
Pitt Pitt | Pitt | Rush | Bur 
Species. Cotton Drew | Muddy | Goose | Joseph | River River | River,| Creek Cae 
(reais Creek, | Creek, Lake, Creek, near near Big near ae 
Oreg.’ Oreg. Oreg. Cal. Cal. Alturas, | Canby, | Valley,) Adin, Ri 
3 Cal. Cal. Cal. Cal. eee 
Entosphenus tridentatus- .- 
Catostomus occidentalis. 
Mylopharodon conocephalus|...-...--- dee 
Ptychocheilus grandis 
Rutilus symmetricus 
Rutilus thalassinus. 
Agosia nubila carrin, 
Salmo clarki. 
Cottus!pulosuse. 5. see seen | see 
xXXKX 
Oregon Lake system. 
Chewaucan Summer Lake . . Alkali 
Warner Basin Basint Basin. | Silver Lake Basin. Basin 
Oph we bh ~ \ u oat ioe Gee ae =) 
PISRM Seer INE PEE WS IG RIR ER es iF 
r 8 | leet a |x| He | eal eel mela 2 
Species. 2 | 3 PS | es| ee ws | ot | ss BS | Re es Fee came] Ss 
S| & [nS | 82/88) Se | 42/22) 2h |4a| 83/8) o |e | ae 
I Oaq¥| Sa| 5 I 2 a o 1S) 
2 | mb sES ao|as|/en|ws |S) ms|.,8]/ag]n8] 2 o wo 
B Re Bo | a £5 I oa |e otal [lane ne SI 
A oR] E a a jas /bs |e S|) oF lin 
s 6 |fa0| 2 | 24)4 BA |S A |saQla |sR] B Sri is 
> | 8 = |o iS) w Dn <4 mn n mn ne AQ {ea} n 
Catostomus warnerensis.... x 
Rutilus oregonensis-........ X x 
Agosia nubila carringtoni... * | X 
Salmojclanki Sesss--sasee ee x x< 
Columbia River system. 
Malheur Basin. 
Species. Silvies Silver Ww. 
River near| Creek near) 7 3" 
Burns. Riley. prings. 
Catostomusmacrochetlus sess == sees ae eaten ee eee eee eee >< | 
Catostomus catostomus - s x 
Acrocheilus alutaceus. ....- x 
Ptychocheilus oregonensis - x 
Leuciscus balteatus. .-- x 
Rutilus columbianus. - x 
Ae osiamubila carringtoni- so. - sess oe eee ee ee eee ee a nee eee eres nee ee errr 
Salmo clarki.~......--- Xx 
Cottus punctulatus 
