PTYCHODEIRA GRACILIS. 341 



equal ; dorsal and lateral ones large, subrliomboid, conspicuously 

 carinated, and acuminated. Abdominal scales posteriorly entire. 

 Posterior aspect of thighs wholly granular. Coloration : one or two 

 longitudinal light streaks on each side, with or without intervening 

 series of black spots. 



SYN.—Pf)/(jo(reres, DuM. & BiBR. Erpet. gen. IV, 1837, 273.— DuM. & A. Dum. 

 Catal. meth. Kept. Mus. d'hist. nat. i, 1851, 72. 

 Pti/chodeira, FiTZ. Syst. Kept. I, 1843, 17 & 73. 

 Pii/goderxiSf Q-RAY, Catal. Lizz. Brifc. Mus. 1845, 216. 



Observ. — In this subgeneric division the neck exhibits longitudinal 

 folds, more or less distinct, but has no scapular fold, thus standing 

 in close relations to Liodeira and Liolaemus, especially if we bear in 

 mind that the sides of the neck are covered with scales similar to 

 those of the body, though smaller. The imbricated and keeled tem- 

 poral scales constitute another relative feature in this genus. 



The species which it includes are more numerous, though further 

 researches may reduce their actual number, and show some of them 

 to be mere varieties of either one or the other. 



1. Ptychodeira gracilis, Grd. 



(Plate XVII, figs. 22-28.) 



Spec. Char. — Cephalic plates smooth. Auricular aperture large, 

 minutely denticulated. Supralabials nearly equal to the labials. 

 Temporal scales moderate. Sides of neck but slightly wrinkled. 

 Dorsal and lateral scales subequal. Abdominal scales smooth, sub- 

 lanceolated. Tail very long and slender. Olivaceous-brown, with 

 two longitudinal streaks on each side : uppermost superiorly lined 

 with black. Sides speckled with black. Beneath pale, unicolor, 

 except the chin and throat, which exhibit sometimes interrupted 

 black lines. 



Syn. — Proctotretus gracilis, Bell, Zool. Voy. Beagle, V, 1843, 4. PI. i, fig. 2. 

 Leiodera gracilis, Gray, Catal. Lizz. Brit. Mus. 1845, 211. 



Observ. — The resemblance of this species, in its general aspect, to 

 P. sta7itoni is very striking, and still more so, when we consider its 

 coloration, which is most similar. 



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