Amphibians and Reptiles of Mexico. 303 



Bufo valliceps, Bufo marin us and Engystomops pustulosus, witli Croco- 

 dilus americanus and Thamnopkis sauritus proximus, were foniid about 

 the ponds, bnt tliese species were represented by only a few indi- 

 viduals, and only T. s. proximus was foiind nowliere eise, These 

 species were, with the exception of the gartersnake, found mucli more 

 commonly about the lowland forest ponds. 



The lowland habitats were by far the riebest in species and 

 individuals. It will nndoubtedly develop that all of the species 

 found on the savannah occur much more numerously in the lowland 

 habitats, and, as has been said, all but three savannah species {Erythro- 

 lamprus imperidlis, Thamnophis sauritus proximus and Cnemidophorus 

 deppei) in our coUection were also found on the lowlands. Upon analysis 

 it is Seen that the lowland forests and the rivers and lakes are the ri- 

 ebest in individuals and species. The Clearings contain principally such 

 ground forms from the forest as are able to live in the more open con- 

 ditions (with the amphibious species that can endure the same con- 

 ditions, e. g., Bana austricola), and the ponds the more aquatic species 

 from the forest with the young of river and lake forms that come 

 to the land to breed (e. g., Chelydra rossirjnonii). 



It is believed, then, that the general Statement can be made 

 that there are two groups of natural habitats in the region-, the 

 forest, and the rivers and lakes. When the lower lands are cleared 

 many of the ground and semi- aquatic forms persist, the former in 

 the rank grass or in the canefields, the latter about the ponds. 

 If the land is higher and extensively cleared and grazed some of 

 the ground forms may still linger in diminished numbers in the 

 clumps of woodland that are not destroyed and most of the aquatic 

 species also in small numbers in the ponds, but the grassland areas 

 constitute conditions so different from those to whicli even the ground 

 forms from the forest are accustomed that very few species persist 

 and these only in very small numbers. 



Acknowledgements. 



In the progress of the work, I have become indebted to a 

 number of persons for very material assistance. To be acknowledged 

 particularly is the assistance of the managers of the hacienda, — 

 Mr. J. C. HiTCHMAN, Gereute, Mr. Thomas La Rüe, Sub-Gerente, 

 Mr. Feank Lehmee and Mr. Philipp Lehmee. Mr. Hitchman kindly 

 permitted us to make the hacienda our headquarters, and Messrs. 

 La Rüe and Feank and Philipp Lehmee, who were on the plan- 



