Mr. A. W. E. O'Shaughnessy on Gerrhonotus. 45 



nasals ; their " internasorqstrale " = the internasal ; and con- 

 sequently their " fronto-internasorostrales " = the frontalia an- 

 teriora. 



List of Species of the Genus Gerrhonotus. 



Group I. Head depressed ; occipital and temporal plates more or less 

 swollen. Scales of back and sides weakly keeled or smooth. 

 Abronia. 



Gerrhonotus Deppii, Wiegm. Herpet. Mexicana, 1834, p. 31, 

 pi. ix. fig. 3. 



Mexico. Type in Berlin Museum. 



G. tce?iiatus } Wiegm. I. c. pi. ix. figs. 1, 2. 

 Mexico. Type in Berlin Museum. 



G. gramineus, Cope, Proc. Acad. Nat. Sc. Philad. 1864, 

 p. 179. 



Mexico. Smithsonian Museum. 

 Apparently closely allied to G. Deppii. 



G.auritus, Cope, I. c. 1868, p. 306. 

 Vera Paz. Smithsonian Museum. 



G. Vasconcellosii, Bocourt, Nouv. Archives du Museum, 1872, 

 p. 107. 



Guatemala. 



Group II. Head not depressed; occipital shields not prominent. 

 Scales of back keeled, the keels forming longitudinal ridges. 

 Gerrhonotus. 



A. Head more or less tapering ; body slender ; tail very long and 



tapering. 



* A small plate interposed between the first supranasals. 



G. tessellatus, Wiegm. 1. c. p. 32. (See Cope, I. c. 1866, p. 321, 

 and Bocourt, I. c. p. 102.) 

 ? Pterogasterus ventralis, Peale & Green. 



Mexico. Types in Berlin Museum and several specimens 

 in British Museum. 



G. lemniscatus, Bocourt, I. c. p. 105. 



Mexico, Vera Paz. 



The British Museum possesses three specimens which I 



