no. 2078. REPTILES OF NORTHWESTERN NEVADA— RICHARDSON. 431 



of 1-2 , while one in the Tahoe series and two in the Carson series 

 have the increased number of two on each side. The postoculars 

 usually number three on each side with asymmetrical variations of 

 2-3 and 3-4, the former the more prevalent. The variations tend 

 toward a reduced number of postoculars. There are usually one 

 anterior and two posterior temporals on each side, but the variants 

 show a definite tendency to increase the posterior number to three 

 and even four. The supralabials are 8-8 with variations of 8-9 

 and more rarely 9-9. Ruthven (1908 p. 144) found that the varia- 

 tions approach a smaller number than eight and indeed noted only 

 one individual out of 218 with the asymmetrical number of 8-9. 

 There are usually ten infralabials, although ten specimens have a 

 larger or smaller number. The reduced number of 9-10 occurs three 

 times, the asymmetrically increased number of 10-11, six times and 

 the increased number of 11-11, once. Ruthven (1908, p. 144) 

 recorded the reduced number of 9 as more frequent than the in- 

 creased number of 11. In the number of dorsal scale rows, the series 

 are divided. Individuals in the Tahoe and Carson series have the 

 formula, 19-21-19-17 more frequently, while 21-19-17 is most 

 prevalent in the Palisade series. Variants with the extremes 19-17 

 and 23-21-19-17 occur in the Tahoe series while the range in the 

 Palisade series is 21-19-17-15 to 21-19-17. The snakes in the 

 Tahoe series have a smaller average number of ventral plates, 169.3 

 in the males against 175 and 175.5 in the males of the Carson and 

 Palisade series. The averages of total length and tail length are 

 considerably lower in the Tahoe series than in the Carson and Pali- 

 sade series. The ratios of tail length to total length for the three 

 series are: males, average, 25.3 per cent; females, average, 22.7 per 

 cent. 



When the average number of variations per individual specimen in 

 the preocular, postocular, temporal, supralabial, and infralabial 

 scales is calculated for each series, it is evident that the Tahoe series 

 shows the greatest amount of variation, averaging 1.03 deviations 

 from the normal per individual. The Carson series is second with an 

 average of one variation, the Palisade series third with an average of 

 0.75 variations per individual. The amount of material is too small 

 to render possible far-reaching conclusions, but it is interesting to 

 note that the greatest variation occurs in the mountain inhabiting 

 individuals, the least in desert inhabiting ones. 



A manifest diversity of coloration is evident when the three series 

 are compared. Twenty-four specimens in the Tahoe series have three 

 distiuct stripes, the median dorsal one, dull white or yellow in color, 

 occupying the median and varying amounts of the proximal half of 

 the row to either side of it, the lateral ones, gray in color, involving 

 the second and all or a part of the third row on each side of the body. 



