1888- ] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 397 



REPTILIA. 



TESTUDIATA. 



Cinosternum flavescens Agass. One specimen. 

 Pseudemys ornata Gray. Two specimens. 

 Cistudo ornata Agass. One specimen. 

 Xerobates berlandieri Agass. One specimen. 



LACERTILIA. 



Oligosoma laterale Say. Not common ; one specimen. 



Eumeces obsoletus B. & G. Eight specimens. 



Cnemidophorus sexlineatus L. Five specimens. 



Cnemidophorus tesselatus. One specimen. 



Sceloporus ? scalaris Wiegm. Seven specimens. 



Sceloporus variabilis Wiegm. Nine specimens. First found in the United States 



near Corpus Christi, by Francis Aaron ; common in Mexico. 

 Sceloporus spinosus Wiegm. Four specimens. 

 Sceloporus sp. Five specimens. 

 Sceloporus torquatus Green. Six specimens. 



Lysoptychus lateralis, gen. et sp. nov. (Plate xxxvi, Fig. 1.) 



Char., gen. — Nearly allied to Sceloporus and Uta. A loose fold across 

 the throat formed by the conjunction of the prehuuieral folds, as in 

 Ctenosaura, not closely folded nor bordered with enlarged scales. Fem- 

 oral pores ; no preanal pores. No dorsal crest. Tympanic disk ex- 

 posed. 



This genus is intermediate between Sceloporus and Uta. The loose 

 dermal neck-fold, like that of some of the larger genera of Iguanidre, 

 is not found in the former. The tightly adherent collar of Uta might 

 have been developed from a Sceloporus through a Lysoptychus. 



Char., specif. — Integument of side of neck thrown into numerous 

 folds. The most prominent is continuous with the collar fold, and it 

 sends out two folds forwards to the tympanic meatus. A second fold 

 is concentric with the base of the humerus at its anterior base ; its su- 

 perior part is prominent and longitudinal, and continues to the fold in 

 front of it. Tail round. 



The scales of the sides are smaller than those of the belly, which are 

 smaller than those of the back. The latter are rather small, counting 

 seventeen longitudinal rows between the small lateral scales of the 

 scapular regions. The keels of the dorsal scales are in parallel lines. 

 Scales of the tail subequal, strongly keeled, except below. Fifteen fem- 

 oral pores. Two postanal plates. 



Interparietal plate large, subround ; parietals small, subpyriform, one 

 fifth as large as the interparietal. Five or six transverse supraorbital 

 plates, separated from the frontals by one row and from the supercil- 

 iaries by two rows of scales. Frontal divided transversely, the anterior 

 part divided longitudinally. These plates are preceded by two platesj 

 and these by three in transverse relation ; two large intemasals sepa- 



