466 



PROCEEDINGS OF THE NATIONAL MUSEUM 



teeth in Rhadinella number 16 and 17, while in two Trimetopon ex- 

 amined they are 11 to 13. Rhadinaea has 16 to 22 teeth in Mexico; 

 thus Rhadinella would appear closer to that genus in this character. 

 Another difference is the character of the hemipenial spines, which 

 are perfectly straight in Rhadinella, hooked in both Trimetopon and 

 Rhadinaea. Finally, the tail is extremely short in Rhadinella, with 

 42 or fewer caudals, while in Trimetopon and Rhadinaea the subcau- 

 dals are 58 or more. 

 The Museum has no others of the species. 



*RHINOCHEILUS ANTONII ANTONII Duges 



A single specimen in the Museum is from Culiacan, Sinaloa (No. 

 46370). 



SALVADORA BAIRDII Jan 



Ten specimens were secured, from the following localities : Guana- 

 juato: Acambaro (No. 109244). Michoacan: Tacicuaro (Nos. 

 109236-42). Puebla: 20 km. south of Puebla (No. 109235). Vera- 

 cruz: El Limon (No. 109243). 



On two occasions specimens were startled in brush, whereupon 

 they raced away with considerable noise, stopping abruptly a few 

 yards away. In both cases the snakes stopped within gunshot, and 

 in spots where they could be seen without change in my own position. 



In eight specimens examined, the maxillary teeth are 9-3, with the 

 exception of No. 109240, in which they are 10-3. The posterior chin 

 shields are closely approximated, usually in partial contact. In one 

 specimen the preocular is single, and in another there are three post- 



Table 30. — Variation in Salvadora bairdii 



