The naked Salamanders and Frogs will occupy the lowest place. By their form, absence of teeth, and mode of life, the Chelonia are allied to them.
Then follow the Serpents and Lizards with a perfect set of teeth. The Serpents are distinguished from the Lizards by their want of feet and the long bifid tongue inclosed within a sheath.
Among the Lizards apodal species occur, as the Blind-worms; but they have under the skin some pedal bones, and are, in addition to this, sufficiently distinguished from the Serpents by the short and sheathless tongue.
Among the Lizards with perfect feet there are some with small visual organs, like as in the Serpents; others with unusually large eyes, e. g. the Chameleon, Gecko, Ichthyosauri, and Crocodiles. All other Lizards, the Serpents, Chelonia, Salamanders and Frogs, have small eyes and consequently follow each other.
The Crocodile has teeth articulated by gomphosis, and consequently resembles the Thricozoa.
I divide the present class therefore into the following groups.
A. DERMAL REPTILES—SMALL-EYED.
Order 1. Protozooid Reptilia-Kröten.
3543. Body slimy and scaleless, or maxillæ devoid of teeth.
Fam. 1. Infusorial Reptiles, Petromyzoid—Caudate Batrachia, Salamanders.