1926] Snyder: The Trout of the Sierra San Pedro Martir 425 



be more explicit — it appears that the representatives of >S. nelsoyii are 

 somewhat more deep, heavy and less trim, the caudal peduncle is 

 deeper, the caudal fin perhaps less deeply notched, the head longer 

 and somewhat blunter, the eye much larger, and the fins somewhat 

 stronger. These very characters are subject to much variation in 

 S. irideiis, however. 



TABLE 5 

 Salmo xelsoni 



In Salmo nelsoni it is found that an increase in the size of the head 

 becomes apparent during the third year of age, as determined by a 

 microscopical examination of the scales. In this connection it will be 

 of interest to mention also that growth seems to be more rapid here 

 than in the trout found farther north. For illustration, two tables 

 are presented, the first (table 5) including the calculated stature of 

 twenty representatives of nelsoni at given ages, and for comparison, 

 a second table (6) including the same data for ten examples of irkleus 

 from the Klamath River. The oldest specimens of nelsoni in the col- 

 lection are in the fourth year of age. Most of the others are in the 

 third year, a few are in the second, while two individuals measuring 

 69 and 95 millimeters respectively are clearly fishes of the year. They 



