l«^<i] Snyder: The Trout of the Sierra San Pedro Martir 423 



In color the species may be considered as a profusely spotted form. 

 In addition to the parr marks, which seem to become indistinct or to 

 disappear entirely with increasing age, the whole upper portion of 

 the body from the snout to the tip of the tail is pretty well covered 

 M^th black spots, especially in the darkest individuals. The spots of 

 the head are very distinct and round. On the opercles they are in 

 some cases a little less distinct in outline, and alwaj^s larger. The 

 spots of the body are not regular in outline, as they are made up of 

 closely associated pigment specks. In some regions they are inclined 

 to be irregularly stellate, somewhat reticulate, or broadly linear. From 

 about the middle of the body to the base of the caudal fin they grad- 

 ually increase in size, an occasional one approaching the pupil in 

 diameter. Not many spots occur below the lateral line, and most of 

 these are small, indistinct, and somewhat linear in outline. These 

 are usually assembled in the region of the pectoral fin and on the 

 caudal peduncle. An occasional specimen is well covered with spots 

 on the entire lateral region excepting the belly. 



The spots on the dorsal fin are oblong and arranged in series, and 

 those of the basal and anterior part of the fin are more nearly circular. 

 The adipose fin is more or less completely edged with black and usually 

 supports one or more round spots. The dorsal edge of the caudal is 

 invariably supplied with from seven to ten well defined spots, while 

 over the entire fin are scattered round or elongate spots, some near 

 the posterior edge being markedly linear. About eleven broad parr 

 marks appear along the lateral line. Alternating with these are 

 smaller ones above and below. The anterior upper edge of the dorsal 

 and the anterior lower edge of the caudal are broadly bordered with 

 light color, as is also the anterior edge of the ventral. The pectorals, 

 ventrals, and anal are without spots, although in some cases they are 

 well diffused with black pigment. 



In order to express the numerical and regional variation in the 

 number of spots with some degree of accuracy, they are tabulated 

 (table 2) for ten individuals. The spots of five individuals of S. 

 irideiis are also arranged in the table. The body, conveniently divided 

 by the lateral line into an upper and a lower half, is quartered by 

 means of a vertical line through the anterior end of the dorsal fin. 

 It would appear from this table that S. nelsoni might be sharply dis- 

 tinguished among rainbow fronts as a color form ; but when the field 

 is widened and individuals from different localities are introduced, it 

 does not stand out so sharply. The figure of a rainbow trout pub- 

 lished in California Fish and Game (5, 1919, p. 114) furnishes a good 



