MEXICAN SNAKES AND CROCODILMNS — SMITH 491 



scales ; in females the curve of variation is somewhat more regular (126, 

 1 ; 128, 1 ; 129, 4 ; 130, 5 ; 131, 7 ; 132, 5 ; 133, 3 ; 134, 2 ; 135, 1 ; 136, 1) , but 

 in males it is considerably spread (122, 5 ; 123, 5 ; 124, 5 ; 125, 5 ; 126, 7; 

 127, 1; 128, 5; 129, 3; 130, 2; 131, 1) ; the counts are insufficient for an 

 accurate estimation of significance of differences between total and the 

 typical ventral count. 



The supralabials are 7-8 in four, 7-7 in the others. The infralabials 

 are 5-5 in 1 ( $ ), 6-6 in 47, 6-7 in 17 (11 9 , 6 $ ), 7-7 in 4 (39,14). 

 In all the preoculars are 1-1; the postoculars are normally 2-2, but 

 fused together on one side in 9 (59,45 ),on both sides in 7(49, 35); 

 two specimens have 2-3 postoculars. There are two anterior temporals 

 on both sides in two, on one side in six ; the secondary temporals are 

 single on one side of one, triple on one side of one, double in others. 

 The loreals are 0-0 in 28 (8 9 , 20 5 ), 0-1 in 13 (79,65), 1-1 in the 

 remainder. In one the suture between the internasal and prefrontal 

 on one side is incomplete; otherwise the internasals and prefrontals 

 are distinct and separate. On one side of one specimen the prefrontal 

 contacts the labials. The second supralabial contacts the preocular on 

 one side in 10 (59,55), on both sides in 54, on neither side in 5. 



The percent of the total length comprised by the tail length varies 

 from 12.7 to 17.6 in 30 females, and from 17.0 to 22.3 in 39 males. 



From lineata varians, of an adjacent range, I. wetmorei differs as 

 follows: 



I. wetmorei I. varians 



ventrals in 9 83 percent 128 or less (25 of 90 percent 129 or more (26 of 



30 29) 



candals in 9 83 percent 31 or less (25 of 80 percent 32 or more (21 in 



30) 26) 



Infralabials 94 percent 6-7 or less (65 in 90 percent 7-7 or more (57 in 



69) 63) 



Between these two races there are a number of other differences of 

 considerable significance, but they are of less than 70 percent occur- 

 rence. From I. acuta there are obvious differences in pattern and in the 

 number of infralabials. 



The race with which I. vjetmorei is to be compared, however, is I. 

 lineata. In 64 females and 60 males of the latter, from the states of 

 Guanajuato, Hidalgo, western Mexico, Michoacan, Morelos, Puebla, 

 and San Luis Potosi, the chief difference evident, from I. wetmorei, 

 is the number of infralabials. In I. lineata, 10 percent have 6-7 in- 

 fralabials or less while in I. wetmorei 94 percent have 6-7 or less. 

 Specimens from eastern Mexico, Distrito Federal, and central western 

 Veracruz (El Limon Totalco, Cruz Blanca, Toxtlacuaya, and between 

 Las Vigas and La Jolla), are intergrades. In 18 specimens from 



