424 



University of California Publications in Zoology [Vol. 21 



example of an excessively spotted individual. The more intensely 

 pigmented examples of 8. nelsoni have the dorsal, anal, and ventrals 

 broadly edged with white, while in lighter-colored individuals the 

 light area is often greatly restricted and much less evident. 



The species appears to exhibit a certain amount of reduction in the 

 number of vertebrae, but until data from carefully prepared material 

 representing a sufficiently extended geographic area are available for 

 comparison the character cannot be relied upon as distinctive. An 

 enumeration of twenty examples of *S'. nelsoni was made. In so doing 

 the vertebral column was entirely denuded of tissue on one side so 

 as completely to expose even the modified tail vertebrae, all of which 

 are included in the count, which is as follows : 



TABLE 3 



Number of specimens.. 

 Number of vertebrae.. 



13 



61 



7 

 62 



A tabulation (table 4) of the number of vertebrae of a series of 

 specimens of Salmo irideiis mostly from the coastal streams of north- 

 ern California will serve for comparison with the above. It will be 

 noted that, while an insertion of the counts of ^S*. nelsoni might be 



TABLE 4 



Number of vertebrae 



Novo River, Northspur 



Eel River, Fortuna 



Klamath estuary 



Klamath River, Hornbrook 



Camp Creek (Klamath) 



Fall Creek (Klamath) 



Bogus Creek (Klamath) 



Mill Creek (Sacramento) 



60 



61 



62 



63 



64 



65 



2 



6 



10 



3 



4 

 1 



8 

 4 

 11 

 17 

 5 

 6 

 4 



9 

 4 

 10 

 13 

 3 

 3 

 4 

 1 



26 



57 



47 



3 



11 



20 



made in this table without seriously changing its general appearance. 

 yet the southern trout would have a decided preference for the left 

 side. 



"When compared directly with examples of Salmo irideus which 

 are at hand — specimens from Coyote Creek and the Pajaro River, to 



