Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/10

 6 THE EXTINCT BATRACHIA, REPTILIA

STEGOCEPHALI.

Usual cranial elements distinct, including frontals and ptcrygoids, and addling "postor-bitals and supertemporals."

Caudal vertebrze1

Urbitosphenoids normal.

Inferior pelvic elements distinct.

Mandible dentigerous; teeth with anchylosed bases, or in shallow alveoli.

Ethmoid.

(A quadratojugal.)

AURA.

Frontal and parietal confluent, nasals wanting or rudimental; other cranial bones present.

Postorbital, supratcmporal, and usually nasals wanting.

Ethmoid an annulus (usually complete above) surrounding cerebral lobes.

Caudal vertebrce lepresented by an elongate compound style.

Inferior elements of the pelvis consolidated into a single vertical mass; ilium attached immediately to sacral lertebrtv.

STEG0€EPIIALI.

X ENORHACHIA.

The vertebral centra not ossified; the teeth simple; no bronchial hyal bones; occipital condyles.

MICROSAURIA.

Vertebral centra ossified; no branchial hyoids; teeth simple or with slightly inflected enamel of the basis; occipital condyles.

GA NOCEPHA LA.

Vertebral centra cartilaginous; branchial hyoids present; teeth with inflected enamel, anchylosed by their bases. No ossified occipital condyles.