152 BULLETIN 61, UNITED STATES NATIONAL MUSEUM. 



for the formula 15 17-15, occasionally exhibited, is the lowest, 

 wliile the highest, 21-19-17, is next to the highest in the genus. 

 The averages, however, reveal a most pronounced tendency toward 

 a formula less than 19-21-19-17. The average formula for Cali- 

 fornia specimens south of Eureka, California, is about 19-17, while 

 north of this point in California, Oregon, and Washington the average 

 for difl'erent localities falls between 17-19-17-(15) and 17-15, although 

 in the Puget Sound series the mean approaches 19-17. 



The variability of the dorsal scale formula is paralleled in the labials. 

 Thus, the supralabials may be 6, 7, or 8, the infralabials 7, 8, 9, or 10. 

 When the averages are taken, however, (figs 64-65), the formula is 

 seen to be reduced. This is less noticeable in the case of California 

 specimens from localities south of Eureka, in which the average 

 is nearer 8/10 than a lower formula, but north of Eureka, as shown 

 by the table, the frequent occurrence of 6 supralabials and 7 or 8 

 infralabials draws the mean number of supralabials down to about 

 7, and that of the infralabials between 8 and 9, the number in both 

 series being slightly higher in the series from Puget Sound. 



The ventral and subcaudal scutes are also variable, so much so, 

 indeed, that in view of the limited number of specimens examined 

 we can only expect approximate results in the averages. When 

 the larger series are plotted (figs. 66-67), however, the results are 

 strikingly similar to those of the dorsal and labial scutes. Thus, the 

 mean number of ventrals for localities south of Eureka is between 

 156 and 162, the subcaudals between 76 and 83, while north of 

 Eureka the average number of ventrals lies between 143 and 152, 

 subcaudals between 61 and 70. Again, in the case of these scutes 

 the number in Washington specimens is highest in the Puget Sound 

 specimens. That the variation in the number of subcaudals is not 

 due to a variation in proportionate tail length is shown by the fact 

 that the latter exhibits no apparent differences throughout the range, 

 and is evidently very nearly, if not exactly, the same as in elegans. 

 In the present material the length of the tail varies from .215 (female) 

 to .28 (male), the averages for different localities being between .23 

 and .26. 



Even from the few specimens that it has been possible to examine, 

 the above tables show that ordinoides as a form is strikingly dwarfed 

 and that the specimens from the localities north of Eureka and 

 toward the coast tend to have fewer dorsal scale rows, labial plates, 

 ventral and subcaudal scutes than those south of Eureka and toward 

 the Cascade range in Washington. From the present data (fig. 68) 

 ordinoides may have either one or tw^o (rarely three) preoculars. 

 From the table it may be seen that the usual number is one and that 

 the occurrence of two preoculars is only occasional. However, the 



