combinations is likewise based upon our previous work. References 
to original descriptions and to a prominent use of the present ar- 
rangement (in case the two designations are not identical) are given 
for all except family names, the latter being formed automatically. 
ommon names are not given, since in most cases none are known. 
The ranges have been, for the most part, only partially recorded and 
for this reason we have been inclined to make them general (for 
the present) rather than too specific. There is a wonderful oppor- 
tunity for further field work and other research on South American 
lizards, since the precise distribution is scarcely known for even the 
most common species, and since very little has been published con- 
cerning their habitats and habits. 
We wish to express here our grateful appreciation to Mr. Karl 
P. Schmidt, without whose help this contribution would surely 
have been much delayed, for criticism of the entire manuscript and 
for a considerable number of bibliographic references; and to Mrs. 
Helen T. Gaige for comments on the Gekkonidae and the Iguanidae, 
as well as for additional bibliographic aid. We are likewise grate- 
ful to the authorities of the many institutions in the United States 
that have allowed us free access to their collections of New World 
lizards and to their libraries, for it is only through such co-oper- 
ation that the appearance of the more authentic and comprehensive 
contributions is made possible. 
