324 Alexander G. Ruthven, 



anus, but in tlie female tliese are so small as to protiude but little 

 beyond tlie scales. Wilder ') states tliat these "are of considerable 

 use in climbing trees". Tliis is certainly not true in this boa at 

 least. 



The specimens obtained were foiind by enganchados in the 

 cane fields. 



TfiamnopJiis sauritus j^t^oxiimis (Say). 



2 specimens captnred about the pools on the savannali at 

 Cuatotolapam. 



The 2 specimens obtained are typical proximus as it occurs 

 in soutliern Mexico. It is interesting to note that the niimber of 

 ventrals (153 and 158) and subcaudals (92 and 95) falls within the 

 limits of Variation shown by the material from this region, and 

 confirms the conclusion advanced by the writer -) that the form is 

 dwarfed in this part of its ränge. 



The only individuals seen were about the margins of ponds on 

 the savannah. It is not improbable that it also occurs along the 

 streams and that the dense Vegetation caused us to overlook it in 

 that habitat. 



Spilotes corias couperii (Holbbook). 



Apparently the most common snake in the region. Found at 

 Cuatotolapam and Lake Catemaco. 



The specimens obtained seem to show that there are not 

 sufficient grounds to Warrant the Separation of Mexican and North 

 American examples or to unite these with the typical S. corias of 

 South America. In all of our specimens the posterior half of the 

 body, both above and below, is black. In the paler ones the anterior 

 part of the back is dark brownish olive (155) and the black cervical 

 mark is rather distinct, but even in these specimens the olive ground 

 color is niore or less spotted with black. while in the darker in- 

 dividuals the back is nearly entirely black. the olive being little 

 in evidence and the cervical mark obscured. The dark specimens 

 differ from North American examples only in the extent to which 

 the black of the posterior part of the ventral surface extends 

 forward. In the pale specimens in our series the blue-black of the 



1) History of the human body, p. 166, New York, 1909. 



2) in: Bull. U. S. nation. Mus., Vol. 62, p. 106. 



