13. COLVBRIDM 



the name T. ordino'tdes couchii. T. o. hammondii often 

 (62%) has two preoculars on at least one side of the head, 

 while T. o. couchii shows no such tendency. T. o. ham- 

 mondii^ however, shows no tendency toward an increase 

 in the number of infralabials, while T. o. couchii does. 



The specimens from San Luis Obispo, Santa Barbara and 

 Ventura counties are perfectly typical hammondii. The 

 localities where intergradation with couchii occurs cannot yet 

 be defined. They are, doubtless, in southern Kern County. 

 Individual variation, in a very few specimens from the San 

 Joaquin Valley, almost bridges the space between the char- 

 acters of typical couchii and hamm.ondii. 



In the San Bernardino Mountains T. o. hammondii occurs 

 with T. o. elegans at altitudes of 5,000 to 7,000 feet. Here 

 the two forms seem to remain true to type, for no inter- 

 mediate specimens have been taken. T. o. elegans seems to 

 be a mountain form while T. o. hammondii occupies the 

 lower country as well as higher elevations. 



The snakes which formerly were recorded as T. ham- 

 mondii from San Pedro Martir Mountains, on re-examina- 

 tion, prove to be T. o. vagrans. T. o. ham-tnondii has been 

 recorded by others from San Antonio and La Guilla, Lower 

 California. 



So far as is known the ranges of T. o. hammondii and 

 T. marciamis do not meet. 



This snake feeds on tadpoles, frogs and fish. 



Captive individuals sometimes change the intensity of 

 their pigmentation very quickly, in accordance with the 

 lightness or darkness of the objects upon which they rest. 



