TEIIDE. 331 
phisbenian type: the pterygoids are largely in contact with the 
sphenoid, the arches are very weak, the columella is so reduced as 
to be hardly distinguishable, and the whole skull forms an almost 
continuous solid mass. 
The premaxillary bone is single, the nasals double, the frontal 
and the parietal single; a small supraorbital bone exists in some 
Ameivas; the palatines are in contact anteriorly ; the maxillary is 
excluded from the infraorbital fossa, which is bounded by the pala- 
tine, pterygoid, and transverse bone, as in Varanus. The head- 
shields are always free from the cranial ossification, a character 
which separates sharply this family from the Old-World Lacertide. 
Limbs, or their rudiments, are present; the degradation begins 
with Proctoporus, which has very short limbs, but with five well 
developed clawed digits ; the limbs are still more reduced in size in 
Scolecosaurus, and the digital formula is incomplete, although claws 
are still present; in Cophias and Ophiognomon, digits are either 
entirely lost or reduced to bud-like rudiments ; and in a species of 
the latter genus, the pelvic limbs have altogether disappeared. The 
clavicle is dilated and perforated proximally; however, Cope men- 
tions Tretioscincus and a species of Scolecosaurus as forming excep- 
tions, having a simple clavicle; the interclavicle is cruciform. 
This family comprises a large number of species, all of which are 
inhabitants of the New World, which show great variety of form 
and scaling. The Yeitde with Lacertoid or Varanoid appearance 
pass, through Crocodilurus and Neusticurus, into the Cercosaurs (to 
which the latter is nearer on account of its separated nasal plates, 
although hitherto placed with the true Teioids). We have then 
several diverging series, the two principal being :—towards Hetero- 
dactylus through Arthrosaura, and towards Cophias through Procto- 
porus. On the other hand, Cophias resembles Heterodactylus in the 
position of the nostril, and the latter genus leads us through Pero- 
dactylus to the Skink-like genera such as Iphisa and Gymnophthal- 
mus, Which all agree with Heterodactylus in the rudimentary con- 
dition (or absence) of the inner finger. And, at last, the vermiform 
Chalcidines by their scaling and cranial structure approach the 
Amphisbeenoids. 
Synopsis of the Genera. 
I, Anterior nasal plates not separated by the fronto-nasal*; limbs 
well developed. 
A. Sealy portion of the tongue not much widened, and not or but 
feebly emarginate posteriorly, frequently retractile into a 
basal sheath. 
1. Ventral plates small, forming more than 20 longitudinal 
series. 
* Separated by several small scales in Callopistes; sometimes separated in 
Teius. 
