SNAKES OF THE GENUS PITTJOPHIS 



37 



between the eye and two supralabials on either side, both of which are 

 obviously specialized characters for the genus. The shape of the ros- 

 tral, also, which is low and flattened in deppei, is intermediate in 

 affinis between the deppei and catenifer groups and vertebralis on the 



25 



, 



31-31-23 

 29-31-22 

 29-51-21 



27-31-22 

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 29-29-20 

 28-29-23 



27-29-22 

 27-29-21 

 27-29-20 

 26-29-21 

 25-29-21 



27-27-21 

 27-27-20 

 27-27-19 



26-27-21 



25-27-19 



deppei i"i' lineaiicollis 



Figure 19. — Variation in number of scale rows in the forms of the deppei group. 



one hand, and sayi and the melanoleucus group on the other. The 

 other scale characters, and the pattern as well, are intermediate in 

 affinis between those of deppei and vertebralis, deppei and deserticola, 

 and deppei and sayi. If deppei were postulated as the ancestral 



