ir Preface. 



alteration in arrangement or nomenclature desirable ; aS, for in- 

 stance, in the case of the genus Eumeces, to which Gunther refers 

 no less than sixteen species, but respecting which assemblage I 

 have preferred adhering to the arrangement in Gray's Catalogue 

 of lizards in the British museum, as at once an easier and more 

 natural classification. 



Then again, I have removed the important family of Homa- 

 lopsidas from their place next the Colubrid^e, to their more 

 natural location alongside of the Hydrophid^e. The Homalop- 

 sidae may be thought to have relations with the Aquatic Colu- 

 bridaB, but these can only be said to be aquatic in the sense of 

 more particularly affecting the vicinity of water than other snakes, 

 whether for food or delectation ; but a fondness for water is not 

 peculiar or restricted to them, as numberless other snakes, the 

 true Colubri, the Cobras and Bungari, &c. equally delight in 

 water and its vicinity. 



Between the Hydrophidte and Homalopsidte on the other 

 hand, the connexion is much stronger and, so to speak, more » 



organic. The Homalopsidc^ are true water snakes, rarely seen on \ 



land ; and being viviparous, are, like the Hydrophidte, not com- 

 pelled to resort to the land for the deposition of eggs. Some of 

 the species too, if not most of them, affect tidal waters, and are 

 equally at home in salt and fresh water. The coloration too of 

 Bome, such as Hipistes, is essentially that of the Hycbophidte ; and 

 Hipistes, being moreover a marine as well as a river species, 

 seems to form a natural link between the two families. 



The curious genus Xenopeltis I have placed next to Python, 

 for no better reason, perhaps, than that it is as much in place 

 there as any where. The brilliant metallic lustre which both dis- 

 play during life, far surpasses what I have remarked in any 

 other snakes. 



Several new genera will be found described in the fol- 

 lowing pages, and some new species. Two species I have re- 

 moved from Ablabes which Gunthcr includes, Ijut my reasons 

 are I think, sound. If such and such a character is of importance, 

 and constantly used as a generic character, as the presence or 



