13. COLUBRID/E 



hammondii. Intergradation between these two subspecies is 

 shown by certain specimens from the San Joaquin Valley, 

 but it seems to be individual rather than geographic. It 

 doubtless will become more evidently geographic when 

 specimens are secured from the proper areas. 



The relationship of T. o. couchii to T. o. vagrans is still 

 closer than to T. o. hammondii. This is shown by the 

 character of the spotting adjacent to the dorsal line when 

 present, the frequent occurrence of more or less dark pig- 

 ment on the gastrosteges, and the fact that in many of the 

 specimens of T. o. couchii some indication of a dorsal line 

 is present. 



In typical T. o. vagrans, as it occurs in Idaho, Utah and 

 eastern Nevada, the dorsal line is well marked, the dorsal 

 spots are very evident and invade the edges of the dorsal 

 line, and the gastrosteges almost always are rather heavily 

 pigmented. T. o. couchii differs from this type of colora- 

 tion in the shortness of or indistinctness of its dorsal line, 

 which may be only a half-inch in length, in the less frequent 

 and less extensive pigmentation of the gastrosteges, and in 

 the absence, indefiniteness, or less characteristic arrangement 

 of the dorsal spots. Intergradation between T. o. couchii 

 and T .0. vagrans is to be looked for in western Nevada. 



The relationship between T. o. couchii and T. o. elegans 

 also is very close. Typical T. o. elegans seems to occur 

 only at considerable elevations in the Sierra Nevada and in 

 the mountains of southern California. T. o. couchii occupies 

 the lower levels, but extends its range up in the Sierra 

 Nevada so far, at certain points, that it overlaps that of 

 T. 0. elegans, just as the range of T. o. hammondii overlaps 

 that of T. 0. elegans in the San Bernardino Mountains of 

 southern California. But, while T. o. hammondii and T. o. 

 elegants seem to remain perfectly distinct and true to charac- 

 ter at the places where their ranges meet, specimens showing 



