40. THAMNOPHIS 



or yellowish white. The belly is yellow or olive, sometimes 

 dusky or washed with brick red. The dorsal line is never 

 bluish. There are four distinct types of coloration, each of 

 which might be considered a distinct species if compared 

 with typical specimens of the others, but all of which pass 

 into one another almost imperceptibly when large series are 

 examined. These types are: 



(a) The ground color brown with three light lines, 

 a pair of dark nuchal blotches and numerous black or dark 

 brown spots along the sides. This style of coloration is seen 

 in young only, but many of the smallest specimens are un- 

 spotted. 



(b) Brown above with three longitudinal lines j the 

 dorsal line yellowj the lateral lines and more or less of the 

 belly bright brick red. 



(c) There are three lines, the dorso-lateral region is 

 largely red with dark spots, and the belly often is more or 

 less suffused with bright brick red. 



(d) Dark olive above with no lateral lines; the dorsal 

 line yellow and very wide, the throat bright yellow, the 

 belly deep olive or slate, with or without a yellow streak 

 along its middle. This is Cope's E. injernalis vidua. 



None of these forms occurs alone in any one place, and 

 the series of intergradations is complete, so that these cannot 

 be recognized as geographical races. Nevertheless, the form 

 "d" without lateral lines seems to occur nowhere else than 

 on the San Francisco peninsula, and the style "c" is most 

 abundant in Marin and San Francisco counties. 



Length to anus .,.._. .175 4-50 475 510 540 560 



Length of tail 58 155 130 178 163 



Variation. — Three hundred and sixty-three specimens 

 show variation as follows: 



The loreal is 1 — 1 in all specimens. Preoculars are 1 — 1 



