Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/11

Rh AND AVES OF NORTH AMERICA. LABYRINTHODONTIA Vera. Vertebral centra osseous; no bronchial hyoids; teeth with much inflected enamel, anchylosed in shallow alveoli. Occipital condyles. Our knonledge of these forms is as yet in many cases too incomplete, to enable us to assert positively as to the structure and position of the teeth, and the preceding arrange-ment is designed to shadow out the true system, rather than to define the groups exactly They may be arranged further in the following manner, with reference to the dermal aunature. I. Three large pectoral plates. a Abdomen with numerous short or long bony scales in close series. 1 A bony sclerotic ring. Teeth simple. Xenorbachia. ..A.mpldbanius. Teeth complex. G«noceph«la. Archegosaurus. No bony ring. Colosteus n. gen. Pholidogaster. Pteroplax. Ceratei pet on. Urocordylus. II. No pectoral osseous shields. a Abdomen with oblique series of long ox short scales. Microsauria. Sauropleura. CEstocephalus. Lepterpeton. Ophiderpeton. Thlonomus. Dendrerpeton. as No abdominal scales known. Pelion. Molgophis. P 1NT 0 12-2. I-1 C I—I I .61. This order I proposed for the reception of the genus Amphibamus Cope, in 1865. I proposed to regard as one of its characters, the existence of opisthoccelian vertebrce. Such impressions were observed in the matrix in which the fossil was preserved, as to induce a