MEXICAN SNAKES AND CROCODILTANS — SMITH 443 



It is noteworthy that two British Museum specimens, recorded by 

 Boulenger (1894 p. Ill), from the Tres Marias Islands (collected 

 by A. Forrer) have higher ventral (185, 186) and a higher caudal 

 (160, 166) count than other specimens. This corresponds with the 

 differences found between mainland Dry march on corals rubidus and 

 the Islands D. m. cleofae; between Constrictor c. imperator and C. 

 c. sioma; Dryadophis melanolomus stu-arti and D. m. slevini; Lam- 

 propeltis triangulum olanchardi and L. t. schmidti; Masticophis 

 flagellum striolatus and M. f. varlolosus ; and completely restricted to 

 the Islands, without close mainland relatives, is Exelencophis nelson i 

 The only snakes known from the Tres Marias Islands that do not 

 show obvious differences from mainland specimens are Oxyoelis acu- 

 minatus, Pelamis platurits, and Agkistrodon oilineatus / a rattlesnake 

 is said to occur, but its identity is unknown (Stejneger, 1899, p. 71). 

 Even some of these three, when known from more numerous specimens, 

 may show differences not now apparent. The race of Leptophis dip- 

 lot ropis from Tres Marias Islands, which lacks a name, is here called — 



*LEPTOPHIS DIPLOTROPIS FORRERI, new subspecies 



Type. — Brit. Mus. Nat. Hist, specimen m of Boulenger's Catalogue 

 of Snakes, vol. 2, p. Ill, 1894, from Tres Marias Islands, collected by 

 A. Forrer. 



Paratype. — Specimen n y of the same Catalogue. 



Diagnosis. — Like Leptophis d. diplotropis, except the ventral scales 

 more numerous (185 to 186 as opposed to 165 to 181), and the caudal 

 scales perhaps usually more numerous (160 to 166 as opposed to 126 

 to 161). 



Description of type. — An adult male, with ventrals 185; caudals 

 160: otherwise as typical of the species. 



LEPTOPHIS MEXICANUS MEXICANUS Dumeril and Bibron 



Seven specimens were secured : Chiapas : Aguacate, near Escuintla 

 (No. 110555) ; Cruz de Piedra, near Escuintla (No. 110556) ; Tonala 

 (No. 110551). Tabasco: Tenosique (No. 110553). Veracruz: Mata 

 de Cana, 25 miles southeast of Jalapa (No. 110557) ; San Juan de la 

 Punta (No. 110558) ; Potrero Viejo (No. 110559). Scale rows 15-11 

 in all; supralabials 8-9 in two, 8-8 in others; infralabials 9-10 in 

 one, 10-10 in one, 12-12 in one, 11-11 in the others; preoculars 2-2 in 

 one (No. 110555), 1-1 in others; postoculars 2-2; temporals 1-2. Re- 

 spectively the ventrals are 160 ( $ ), 151 ( $ ), 160 ( $ ), 155 ( $ ), 



169 ( ? ). 164 ( $ ), 157 ( $ ) ; caudals 157, 149, 151, , 167, 150+ , 



152+. 



The Museum has two others, so identified but not checked by me, 

 from Orizaba, Veracruz (No. 30493), and Altamira, Tamaulipas (No. 

 46524). 



