Of the families thus characterised, some only have distinct eyelids, as the families _Acontiadæ_, _Ophiomoridæ_, _Sepsidæ_, and _Scincidæ_; while others have the eyelids rudimentary and the eyes exposed, as the families _Lialisidæ_, _Aprasiadæ_, _Pygopodidæ_, and _Gymnopthalmidæ_. In the _Acontiadæ_ the nostrils are placed in the enlarged rostral plate, with a longitudinal slit behind. The form of the body much resembles that of our common Orvet, or Blind-worm, and their limbs, when present, are so rudimentary that they can aid little in locomotion. One genus, _Acontias_, is without limbs, and the eyes are furnished with a lower lid, while the upper eyelid is rudimentary. Of this, one species, _A. meleagris_, inhabits South Africa; and another, _A. Layardii_, has been discovered in Ceylon. The genus _Nessia_ has four rudimentary limbs, and the rostral shield is large, sub-conical, and depressed. In one species, _N. monodactyla_, the limbs are diminutive, the posterior placed far apart from the anterior, all being very short, weak, and undivided into toes. In another, _N. Burtoni_, each foot is divided into three minute toes. Both species are peculiar (so far as known) to Ceylon, and the habits of this family are much the same as those of our common Orvet (_Anguis fragilis_). The family of _Ophiomoridæ_ is founded on a single genus and species, _Ophiomorus miliaris_, which inhabits North Africa. As remarked by Dr. Gray, this reptile seems to be intermediate to the _Acontiadæ_ and the _Scincidæ_, and makes it appear as if the large rostral shield of the former was formed of the united rostral, supra-nasal, and nasal shields of the present family, and of the _Scincidæ_. It has an elongate, cylindrical body, without external limbs, and the ears are hidden under the skin; the eyes are distinct, with valvular eyelid; and the scales of the body and somewhat elongate tail are hexagonal.