354 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



eighth. None in this set showed the increase to 1 1 infralabials which 

 is known to occur in specimens from this part of the State. Among 

 the specimens showing variation in this character 27 per cent are 

 males. 



Per cent. 



10 normal 78 



10-9 asymmetrical 14 



9 symmetrical 2 



9-8 asymmetrical 4 



8 symmetrical 2 



One specimen, Cat No. 53574, U.S.N.M. (Orig. No. T-136), a female, 

 shows marked asymmetry, there being 10 shields on one and 8 shields 

 on the other side. This is the specimen in which many of the gas- 

 trosteges are incomplete. 



Variation in Geneials. 



The anterior and the posterior paii^ may be equal in length, one 

 pair may be longer or shorter than the other, and it often occurs that 

 there is much discrepancy between the length of the right and left 

 posterior shields. In spite of these facts, this purely book character — 

 the relative length of the anterior in terms of the posterior pair of 

 geneials — has been made use of in the attempt to separate this com- 

 plex Pacific Coast garter snake into endless species. 

 Variation in Gulars. 



The gular shields that he between the posterior geneials and the 

 first gastrostege are irregularly paired anteriorly and azygos poste- 

 riorly. The normal count is two paired and two unpaired shields. 

 The variation ranges from four paired and one unpaired to one im- 

 paired and four azygos shields. 



SUMMARY OF VARIATIONS. 



The following may be assumed to be the normal conditions: 



Ter cent. 



Scale rows, 19-21-19-17 56 



Preocular, 1 : 90 



Postoculars, 3 96 



Anterior temporal, 1 98 



Posterior temporals, 2 92 



Supralabials, 8 90 



Infralabials, 10 78 



Anal, entire 100 



Urosteges, paired 94 



The following table shows the percentage of normal individuals 

 and the percentage of those that are abnormal in one or more char- 

 acters: 



Per cent. 



Normal in all characters 38 



Abnormal in one character 30 



Abnormal in two characters 22 



Abnormal in three characters 8 



Abnormal in four characters 2 



