CHAPTER VIII. 



SOME OBSERVATIONS ON LIZARDS. 



(LacertUia.) 



E very much need a complete treatise upon the United 

 States Reptilia, fully illustrated, with a companion 

 volume upon the Amphibia of this country. No such 

 work has as yet been published, and our herpetologists 

 are, at this writing, still depending upon a literature of the sub- 

 ject, which is rapidly becoming more or less antiquated. Usu- 

 ally, naturalists include in the Reptilia a variety of orders of ex- 

 tinct reptiles, as well as the more modern groups of Crocodilia, 

 LacertUia, Ophidia, and Chelonia, while in the Amphibia we find 

 the Urodela, the Anura, the Peromela, and the Labyrinthodonta. 



Such a work should fully review up to date the entire history 

 and literature of the subject; give the general characters of the 

 Class Reptilia; their taxonomy or classification; their morphol- 

 ogy or anatomy; the known extinct forms of Keptiles and Am- 

 phibians (palaeontology) ; and the distribution and biology of the 

 existing orders. 



It is possible that the U. S. National Museum may publish 

 before long a valuable work upon our United States reptiles, as 

 I am aware that shortly before his lamented death, Professor 

 E. D. Cope had completed a work of the kind. 



As Dr. Gtinther of the British Museum has remarked, " The 

 name Lizard (Latin lacerta) originally referred only to the small 

 European species of four-legged reptiles, but is now applied to a 

 whole order (Lacertilia), which is represented by extremely nu- 

 merous species in all temperate and tropical parts of the globe. 

 Lizards may be described as reptiles with a more or less elon- 

 gated body terminating in a tail, and with the skin either folded 

 into scales (as in snakes) or granular or tubercular; legs are 

 generally present usually four, rarely two in number but 

 sometimes they are reduced to rudiments or entirely hidden be- 

 low the skin; the jaws are toothed, and the two mandibles firmly 

 united in front by an osseous suture. Eyelids are generally pres- 

 ent. The vent is a transverse slit, and not longitudinal, as in 



