Mr. Gray's Description of a new Genus of Saurian Reptiles. 207 



subsidence must have been connected with a corresponding 

 fall of the neighbouring ocean. In no other way can that great 

 reservoir have di'avvn off' the saline, the mixed, and the fresh 

 waters, which in succession have covered the bottom of our 

 valleys; nor without such an internal change in its own rela- 

 tive state, could it have effected those revolutions, which have 

 altered the face of an extensive district, and the progress of 

 which may be traced alike in the memorials of nature and the 

 records of man. 



XXXVIII. A Description of a. new Gemis and some new Spe- 

 cies of Saurian Reptiles; with a Revision of the Species of 

 Chameleofis. Bj/ J. E. Gray, F.G.S. <$'c. 



To the Editors of the Philosophical Magazine a7id Annals. 

 Gentlemen, 

 TJ^OLLOWING the maxim of the great Linne, " Nulla 

 -■- dies sine linea," I have sent you the descriptions of a few 

 new reptiles which are in the British Museum, along with a 

 revision of the Chameleons, which I had found very much em- 

 broiled by the compilations of former naturalists, when I was 

 lately engaged in naming the species in the above collection, 

 along with some corrections of my former paper. 



J. E. Gray. 



Fam. IGUANID^. 



Leiocephalus, n. g. 



Caput scutatum ; corpus et Cauda eequaliter squamosa, pori 

 femorales nuUi ; digiti inaequales siraplices ; dentes denticulati, 

 palatini perparvi. 



Head and eyebrows shielded ; body and tail uniformly scalv; 

 femoral pores none ; toes unequal, simple ; teeth denticulated, 

 palatine teeth very small. 



This genus has very much the external appearance of the 

 Agamce ; indeed so much, that before 1 was able to examine 

 its teeth, I was led to consider it as forming a section of that 

 genus; but the teeth, which may be considered as one of the 

 best characters for determining the natural relations of this 

 kind of animals, place it with the Iguame. 



In this family it is most nearly allied to the second section of 

 the genus Lophyrus, which appears to be the intermediate link 

 between the true hophyri and the Leiocephali ; but it is innne- 

 diately distinguished from the latter, by the head being re- 

 gularly shielded, and not provided with a large single occi- 

 pital perforated shield. The shields of the head are peculiar: 



they 



