NATURAL SCIENCES OF PHILADELPHIA. 61 



separated by a shield : three pairs of parietals in a longitudinal series. Oc- 

 cipital region irregularly shielded. Supraorbitals two. A median chin shield 

 behind the srmphyseal. Greenish olive, irregularly speckled with darker. A 

 greenish white vertebral stripe. A lateral black greenish-white bordered band 

 from in front of the eye to the thigh. Beneath greenish white. 

 Hab. Andes of Western Equador. 



Ameiva Cuvier. 



For convenience of analysis, this genus may be divided into the following 

 sections, nearly as has been done by Dr. J. E. Gray. 



Inner aspect of heel without spinous tubercles. 



Abdominal shields in eight longitudinal rows A 



Abdominal shields in ten longitudinal rows, (supraoculars four) B 



Abdominal shields in twelve or more longitudinal rows C 



Inner aspect of heel with spinous tubercles D 



No species belonging to any of these groups exists in the nearctic region; 

 there their place is supplied by an extensive development of the genus Cnemido- 

 phorus. Section A (embracing eight species) is characteristic of northwestern 

 South America and Mexico, though two of the species, forming a subgroup, 

 are West Indian. The latter seems to be allied to Cnemidophorus through the 

 West Indian and South American species of the latter, while the connection of 

 that genus with the former subgroup is maintained by some of the Cnemido- 

 phori of the North American deserts. Ameiva guttata approximates in size 

 and coloration to section B. With A. undulatait marks the northern limit 

 of the genus on the American continent, viz., about the latitude of Vera Cruz. 

 Of sections B, C and D, eight are insular, five continental. Of the former, 

 so far as is yet ascertained, two species appear to be peculiar to Cuba, one to 

 New Providence, one to Sombrero, one to Jamaica, one to Santa Cruz. One 

 species is said to be common to Hayti, Porto Rico, St. Thomas, Santa Cruz and 

 Martinique. The continental A. surinamensis inhabits Trinidad : small 

 specimens from Paraguay closely resemble the young of the same. The genus 

 does not seem to occur on the Pacific slope of the Andes, unless the Cnemido- 

 phorus undulatus, mentioned by Giinther (Proc. Zool. Soc, April, 1860) 

 as having been brought from Guyaquil, belongs to it. 



In preparing the present synopsis, I have availed myself of the Erpetologie 

 Generale and the work of Dr. Gray. In the latter, an A. murina from 

 Surinam is mentioned, of which little can be ascertained. Prince Neuwied has 

 described (Rept. Brazil, p. 180) an A. cyanoni elas from Southeastern Brazil, 

 to which I can only allude, on account of imperfections in the description. It 

 resembles A. eutropia, but belongs probably to section B. 



A 



I. Plates of the caudal whorls carinate superiorly. 



a. Median gular scales very large, plate-like. 



*Premaxillary teeth six or seven. 



A. quadrilineata Cope. 



Cnemidophorus quadrilineatus Hallow., Proc. Acad. Nat. Sci. Phila. 1860, p. 483. 



Three supraorbitals, sometimes a minute posterior fourth ; marginal supra- 

 orbitals five, second very long. Occipitals three. Large gular scales nume- 

 rous, graduating into the smaller. Plates of the fold in two rows, six or eight 

 in the longest. Two antebrachial series, the posterior continuous with the 

 single brachial ; postbrachials large, one principal row. Four femoral rows, 

 two complete tibial, the second and third shields of the external very large. 

 External digit equalling or exceeding extremity of internal. Preanal plates in 

 a single series, the posterior largest. Above olive brown. Two narrow yellow 



1862.] 



