B AS C ANION VETUSTUS. 227 



between them. Scales smooth, disposed upon seventeen longitu- 

 dinal series. Preanal scutella subdivided. Subcaudal scutellae 

 disposed upon a double series. Adults unicolor ; young blotched. 



SYN.—Bascanion, B. & G. Catal. N. Ainer. Kept. I, 1853, 93. 



Observ. — The head is elongated, narrow, and deep; the eyes very 

 large, and the vertex plate elongated and narrow also. The upper 

 anteorbital is much larger than the lower one, which is situated in a 

 notch between two labials. The fourth upper labial is produced 

 behind the eye to meet the lower postorbital. The abdominal scu- 

 tellae are from one hundred and seventy to two hundred in number, 

 the preanal being divided; and ninety to one hundred and ten sub- 

 caudal ones, all of which are divided, or else disposed upon a double 

 series. 



The teeth, as for as our observations go upon the species described 

 below, are pretty nearly equal in development upon the palate as well 

 as upon the jaws ; the premaxillary teeth being wanting. 



BaSCANION VETUSTUS, B. & G. 



(Plate VIII, figs. 12-19.) 



Char. spec. — Capitis longitiidine, tra7is sc2itos supraoculares, dimi' 

 dium intervalli inter apicem rostri et extremitatem posteriorem scu- 

 torum occipitalium, adaequante. Inferiore postorhitali scuto in anqido 

 inter quartani et quintam lahialem sito. Colore supra fusco-olivaceo, 

 infra palleo-viride. 



Spec. Char. — Width of the head, across supraoculary plates, equal to 

 half the distance between apex of rostrum and posterior extremity 

 of occipital plates. Inferior postorbital in a notch, between the 

 fourth and fifth labials. Olive-brown above ; pale-green beneath. 



Syn. — Bascanion vetustus, B, & G. Catal. N. Amer. Kept. I, 1853, 97. 



Descr. — The head is declivous upon the frontal region. The snout 

 is rounded, protruding considerably beyond the lower jaw. The 

 rostral plate is pyramidal and well developed ; the prefrontal plates 



