(2) The head moderately elongated and the parietals diverging from each other for a certain space as they rise upon the side of the head, enlarging the cerebral cavity and the frontal sinus.
- Amphicoelous; parietals separate; clavicles dilated and with a perforation near the ventral end.
- Amphicoelous; parietals separate; but the nasal bones are fused together, and the clavicles are not dilated.
- Procoelous; parietals united; eyelids functional; clavicles expanded as in the true geckos which they resemble in other respects.
- Tailed, lacertiform or serpentiform batrachians, with the temporal region of the skull roofed over by postorbital, squamosal, and supratemporal plates similar to the same bones in Crossopterygian fishes, and likewise with paired dermal bones (occipitals and post-temporals) behind the parietals and supratemporals.