Dr. J. E. Gray on several new genera of Reptiles. 437 



viously described, the female being 9^ lines instead of 10, and 

 the male only 8 lines in length. 



The antennse, as I supposed, consist only of four joints; the 

 second is longer than the third and fourth together ; it is jo?75- 

 matic, with three longitudinal furrows, and not compressed as 

 previously stated. The third and fourth joints are nearly equal 

 in length, the fourth being perhaps a little longer than the 

 third ; they are much thinner than the second ; the third is 

 prismatic, like the second; the fourth elliptical, elongated; the 

 third joint is black and hirsute, like the second; the fourth 

 orange, somewhat pilose, with the base black. 



The anal apparatus of the male, when viewed from beneath, 

 appears to consist of a plate of a semicircular form, broadly 

 notched on its posterior margin, and occupying a broad emargi- 

 nation of the last abdominal segment; viewed from above it 

 presents a nearly circular horny ring, the upper portion of which 

 is very narrow, whilst the lower is produced and emarginate pos- 

 teriorly ; the opening of the ring is narrowed and rendered irre- 

 gular by a large tooth on each side, close to which the margin 

 of the ring is clothed with yellowish hairs. 



I may add, in order to remove all doubts, as to this insect 

 having attained its perfect state, that 1 have in my collection a 

 specimen of its nympha or larva in the last stage of the meta- 

 morphosis, which presents all the customary marks of its im- 

 perfect condition. 



XLVI. — Descriptions of several new Genera of Reptiles ^ principally 

 from the Collection of H.M.S. Herald. By J. E. Gray, Esq., 

 Ph.D., F.R.S., V.P.Z.S. &c. 



To the Editors of the Annals of Natural History. 



Gentlemen, 



Sir John Richardson having kindly allowed me to examine 

 the reptiles brought home by this expedition, I send for in- 

 sertion in your pages characters of the following new genera, 

 which will be figured in the forthcoming work on the Zoology of 

 that Voyage. 



I am, Gentlemen, yours &c., 



British Museum, Nov. 15, 1852, J. E. Gray. 



Iguanid^. 



Section Basiliscina. Nostril lateral ; back of head with a crest 

 of compressed skin ; throat with a cross fold behind ; hinder toes 



