ANGUIDZE. 265 
Fam. 9. ANGUIDA. 
Ophisauroidea, part. Chalcidoidea, part., Anguinoidea, Fitzinger, 
Neue Classif. Rept. 1826. 
Autarchoglosse, part., Wagler, Syst. Amph. 1880. 
Ptychopleuri, part., Scinci, part., Wiegmann, Herp. Mex. 1834. 
— part., Scincoidiens, part., Duméril § Bibron, Erp. Gén. 
v. 1839, : 
Zonuride, part., Scincide, part., Gray, Cat. Liz, 1845. 
Anguidee, Gevilionatiies, Cope, Proc. Ac. Philad, 1864. 
Anguidee, Boulenger, Ann. § Mag. N. H. (5) xiv. 1884. 
The tongue is composed of two distinct portions: a principal 
posterior, thick, covered with villiform papille ; anda small anterior, 
thin, emarginate, covered with lepidoid imbricate papille, extensible 
and more or less retractile into a sheath formed by a transverse fold 
at the anterior extremity of the villose portion. This retractility of 
the distal part of the tongue appears to be constant, though more 
accentuated in some species than in others *; but it should be borne 
in mind that when the tongue is fully extended, every trace of the 
transverse fold or sheath disappears, which accounts for the seeming 
exceptions presented by spirit-specimens in that condition. 
The dentition varies from the strictly pleurodont tubercular teeth 
of Ophisaurus apus and some Diploglossi, through the conical teeth 
of the majority of species, to the curved fangs of Anguis. The 
dentition of the latter has no other equivalent but that of Heloderma, 
to which it bears considerable resemblance; and Leydig has even 
discovered the presence of a slight groove along the anterior surface 
of the teeth which appears to be homologous with the anterior groove 
of the poisonous Lizard’s fangs; the teeth of Anguis are likewise 
remarkable for the comparatively feeble attachment to the jaws, as in 
Heloderma and the Snakes. The new teeth do not hollow out the 
base of the old ones, but originate between them. The palate is 
either toothless, or teeth may be developed on the pterygoids or even 
on the palatines and vomers (Ophisaurus). 
The skull belongs to the normal Lacertilian type. The pre- 
maxillary is single; nasals distinct; frontal single in Gerrhonotus, 
double in the other genera; parietal single; palatines and ptery- 
goids well separated along the medial line; infraorbital fossa 
bounded by the palatine, pterygoid, transverse bone, and maxillary. 
Dermal cranial ossifications are present, which roof over the supra- 
temporal fossa. The limbs may be more or less developed, or 
entirely absent externally, in which case, however, the rudiments of 
the pectoral and pelvic arches are always present. The clavicle is 
slender, and the interclavicle, in the species with well-developed 
limbs, cruciform. Abdominal ribs are absent. 
The body is protected by bony plates underlying the scales, which 
* The common Slow-worm may be taken as a fair example, showing this 
structure developed to a moderate degree. 
