MEXICAN SNAKES AND CROCODILIANS — SMITH 451 



colored young, like the adults, and occurs only on the coastal plain; 

 the other (australis) has very distinctly striped young, and occurs 

 only on the plateau ; in the eastern part of the plateau intergradation 

 of the two forms occurs. 



M. t. australis accordingly remains an important link in the evolu- 

 tionary history of taeniatus, linking ruthveni with schotti and girardi. 

 Retention of the juvenile stripes in the adults led to girardi and 

 schotti, while loss of them completely, even in juveniles, led to 

 ruthveni. 



MASTICOPHIS TAENIATUS GIRARDI (Stejneger and Barbonr) 



Masticopliis taeniatus girardi Smith, Journ. Washington Acad. ScL, vol. 31, 

 p. 393, 1941. 



One specimen (No. 105300) was collected on La Cuchilla Mountain, 

 5 miles south of San Pedro, Coahuila. The Museum has one other 

 Mexican specimen, from "Chihuahua" (No. 14272). 



Respectively, these specimens have 15-11, 15-12 scale rows ; 205 ( 9 ) , 

 208(9) ventrals; 123 + , 259 caudals; 2-2 preoculars and postoculars; 

 1-2, 2-2 temporals. 



MASTICOPHIS TAENIATUS RUTHVENI Ortenburger 



Masticopliis taeniatus ruthveni Smith, Journ. Washington Acad. ScL, vol. 31, 

 pp. 392-393, 1941. 



One specimen was secured, 22 km. north of Victoria, Tamaulipas 

 (No. 111279). The Museum has two 5S other Mexican specimens, 

 from Soto La Marina (No. 37546) and 50 miles south of Brownsville, 

 Tex. (No. 64681), Tamaulipas. 



All are males, with 10-10 infralabials, 2-2 preoculars and post- 

 oculars, and 2-2 temporals (except on one side of one, with 2-3) ; 

 respectively the scale rows are 15-12, 15-13, 15-13; ventrals 189, 197, 

 196; caudals 147 + , 146 + , ? ; supralabials 8-8, 7-8, 8-8. 



♦MICRUROIDE8 EURYXANTHUS (Kcnnicott) 



Four Mexican specimens are in the Museum, including the type 

 (No. 1122) 59 from Sonora; another (No. 1131) bears the same data; 

 No. 8566 is from Tiburon Island, Sonora; and No. 8850 is from 

 Chihuahua. 



88 Ortenburger, 1923, p. 8. 

 w Kennicott, 1860, p. 337. 



