156 BULLETIN OF THE BUREAU OF FISHERIES. 
Not only are the species few in number, but their distribution is very irregular, there 
being as many as 4 or 6 forms in some streams, while in others equally large there 
are but 1 or 2 or even none at all. 
Following the coastal streams southward in serial order from the Columbia, 
and enumerating those which have a fluvial fish fauna, they are found to contain 
species as follows: Nehalem, Catostomus macrocheilus; Nestucca, Agosia nubila; 
Yaquina, A. nubila; Siuslaw, C. macrocheilus, Ptychocheilus umpque, Leuciscus 
balteatus, A. nubila; Tsiltcoos, C. macrocheilus, P. umpque, L. balteatus; Takenitch, 
P. umpqux, L. balteatus; Umpqua, C. macrocheilus, P. wumpque, L. balteatus, Rhein- 
ichthys evermanni, Hybopsis crameri, A. nubila; Coos, C. macrocheilus, A. nubila; 
Coquille, C. macrocheilus, A. nubila; Flores, C. macrocheilus; Sixes, C. macrocheilus; 
Rogue, Catostomus rimiculus; Mad, Catostomus humboldtianus; Eel, C. humboldt- 
ianus; Bear, C. humboldtianus; Navarro, Rutilus symmetricus; Gualala, R. sym- 
metricus; Russian River, Catostomus occidentalis, Mylopharodon conocephalus, 
Ptychocheilus grandis, R. symmetricus. 
No great difficulty has been met in determining the relationships of these 
species. They are representatives of forms found either in the Columbia, Klamath, 
or Sacramento rivers.* Some are identical in every respect with the species of the 
larger basins, while others show a varying degree of differentiation, as described in 
the following pages. In no case, however, does the relationship appear doubtful. 
One stream only, the Rogue, contains a Klamath form. North of the Rogue the 
fluvial species are representatives of the Columbia fauna, while south of the Klamath 
they belong with the Sacramento. This interesting condition of distribution is 
graphically shown on the appended map, where rivers having representatives of 
the Columbia fauna are outlined in red, the Klamath in green, and the Sacramento 
in orange. Rivers in which fluvial fishes are not known to occur are traced in black. 
The following species are described as new: Catostomus humboldtianus; Pty- 
chocheilus umpque; Rhinichthys evermanni; Hybopsis cramert. 
A table has been prepared to show where specimens of each form have been 
collected, thus avoiding the long catalogue of localities which would otherwise appear 
after each species. The trout and salmon are not included in the table. 
a Rhinichthys evermanni is a possible exception. It does not appear to be closely related to R. dulcis of the Columbia, 
The genus does not occur in the Klamath or Sacramento. Reference may also be made to the well-known fact that the 
Columbia, Klamath, and Sacramento basins have each a distinctive fluvial fish fauna, consisting in many cases of character- 
istic species and genera. 
