462 THE AMERICAN NATURALIST [Vol. XLII 



distal third is mottled so heavily with black that the 

 stripe, as such, is lost. The large number of specimens 

 examined indicates that the typical P. c. erythronotus is 

 not more common here than the red intermediates. 



The transition between the variety erythronotus and 

 the red form is accomplished thus: the red dorsal stripe 

 first extends cephalad covering the whole top of the head 

 where there is found in all intermediates a sprinkling 

 of brown dots (Fig. 5). It then invades the sides 

 of the head passing to the snout underneath the eyes. 

 From this position it spreads in all directions, replacing 

 the brown until the whole body is thoroughly suffused 

 with red. In such specimens the brown color-pattern is 

 evident but subdued by the red tone due to the invasion 

 of this color into the whitish areas between the clusters 

 of brown blotches. 



The further transition consists in the expansion of the 

 red ground-color and the gradual reduction of the brown 

 blotches which persist longest on the top of the head, 

 along the dorsal abrupt border of the lateral band, down 

 the middle of the back and on the tail. In the Beesemer 

 specimen only the vestiges of the brown markings remain 

 in the regions just mentioned. On the limbs the invasion 

 of red proceeds from the base towards the extremity, the 

 brown markings showing longest upon the hands and feet. 



In the Buffalo specimen the brown markings are every- 

 where apparently obliterated excepting upon the tail, the 

 snout and the region between the eyes and a cluster just 

 behind and below the left eye. In the alcoholic specimen 

 there are revealed, along the sides of the back in the 

 shoulder region, very fine specks of brown pigment ar- 

 ranged in a narrow band which can be traced to the leg 

 region, although the dots are faint and much scattered 

 in the caudal half, and in the living specimen did not 

 show at all. 



According to Cope 4 intermediate specimens between 



* Cope, op. cit., p. 136. 



