INTRODUCTION. 
More than fifteen years have elapsed since the first sheets of this Volume of the 
‘Biologia Centrali-Americana’ were published. The slow progress of the work was 
due partly to the demand made upon the author’s time by other, chiefly official, 
duties, and partly to the anticipation of receiving important additions to the material 
that was then available at the British Museum, and which included the rich collections 
brought home by Salvin, and later by Godman, from Guatemala and Mexico. A staff 
of collectors was at work for the ‘ Biologia’ in various parts of Central America, and 
they had received instructions from the Editors to pay attention to Reptiles and 
Batrachians, besides the special branches to which they devoted themselves principally. 
To wait as long as possible for the result of these instructions seemed to be all the 
more desirable as the great work of the ‘ Mission Scientifique au Mexique et dans 
l’Amérique Centrale,’ in which the Herpetology was entrusted to the able hands 
of M. Bocourt, was in course of publication, and, like the numerous important 
contributions by the late Mr. Cope, contained a multitude of forms not represented 
in the English collections. 
Of the material received from the above-mentioned sources during the progress of 
the work I have to refer specially to the following :—from Mr. H. H. Smith, who sent 
several large collections from Atoyac in Vera Cruz, Teapa in Tabasco, Omilteme and 
Amula in Guerrero, and Cuernavaca in Morelos; from Hr. A. Forrer, who visited 
the Tres Marias Islands, and thoroughly searched several localities in Western Mexico, 
particularly Presidio, near Mazatlan ; from Dr. A. C. Butler, who selected some localities 
on the plateau of Central Mexico as his collecting-grounds ; from Hr. C. T. Hoge and 
Sefior M. Trujillo, who sent not a few interesting species from Jalapa and Misantla in 
Vera Cruz; from Mr. G. F. Gaumer, who collected in Yucatan and Honduras, visiting 
Cozumel, Bonacca, and Ruatan Islands; from Mr. W. B. Richardson and Hr. Ernst 
Rothschuh, both of whom made valuable collections at Matagalpa in Nicaragua; from 
