TYQOVOmDX. 



239 



Fam. 4. PYGOPODID-ffi. 



Scincoidiens, part., Cuvier, Rkgne Anim. ii. 1817. 

 Gymnophthalmoidea, part., Fitzinger, Neue Classif. Rept. 1826. 

 Autarchoglossse, part., Wagler, Syst. Amph. 1830. 

 Gymnoplithalmi, part., Wtegmann, Herp. Mex. 1834. 

 Scincoidiens, part., Dumeril ^ Bibron, Erp. Gen. v. 1839. 

 Pygopidse, Gray, Cat. Liz. 1845. 

 Aprasiadse, Gray, I. c. 

 Lialisidse, Gray, I. c. 

 Pygopodidse, Boulenger, Ann. 8f Mag. N. H. (5) xiv. 1884. 



The premaxillary is single, narrowed, and much produced pos- 

 teriorly between the nasals, in the long-snouted Lialis quite as much 

 as in the Varanidce ; the nasals are distinct ; the frontal is single ; 

 the prse- and postfrontals are in contact, separating the frontal 

 from the orbit ; the parietals remain distinct, except in Lialis ; the 

 jugal is rudimentary, there being no postorbital arch ; a postfronto- 

 squamosal arch is also absent ; the pterygoids are widely separated 

 and toothless. The mandible contains only four bones, the angular, 

 supra- angular, and articular having coalesced. The dentition is 

 pleurodont. The teeth are small, numerous, and closely set ; in 

 Lialis they are recurved posteriorly, very acute, and swollen at the 

 base, thus resembling those of the Varanidce, whilst in the other 

 genera they do not diverge from the normal pleurodont type, being 

 obtusely pointed and with long cylindrical shafts. The skin of the 

 head is quite free from the cranial ossification, and there are no 

 supraorbital bones. The serpentiform body is destitute of functional 

 limbs ; the fore limb is entirely absent, while the hind pair is 

 visible externally as a scaly flap, most developed in Pygopus, in 

 which the bones of the limbs may be felt more or less distinctly ; 

 when the skin is removed, in Pygopus, the foot, with five ossified 

 toes, is seen most plainly, especially in the males ; the ischium 

 appears externally as a small spur on each side behind the anal 

 cleft. The sternal apparatus exists in a rudimentary state. The 

 tail is long and fragile. The eyes are rather small, with elliptico- 

 vertieal or subelliptical pupil, and not protected by movable lids. 

 The ear is either exposed or concealed under the scales. The tongue 

 is fleshy, papillose, elongate, more or less feebly incised anteriorly, 

 and extensible. The body is covered with roundish imbricate 

 scales, and the head is more or less regularly plated. Prseanal 

 pores are frequently present. 



To place this family in the system is a matter of some diffi- 

 culty. Though formerly associated with, or placed near, the Skinks, 

 the Pygopods have nothing in common with them except superficial 

 appearance. The structure of the skull is most similar to that of 

 Geckos, but differs in two points : — (1) the separation of the frontal 

 from the orbit by the union of the prae- and postfrontal, a character 



