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Show 480 ON THE TRIASSIC REPTILE TELERPETON ELGINENSE. [Apr. 19, the Mammalia through the Anomodontia, the Cotylosauria being a side-branch issued from the Pariosauria. The Rhynchocephalia may have been evolved out of the Microsauria, and branched off into many phyla, one of which culminated in the Birds. My objection to the Chelonia and Plesiosauria being placed with the Pariosauria or Anomodontia rests on the ground that it cannot be conceived that these two orders could have been derived from forms in which the quadrate is more or less reduced, the plastron, or system of " abdominal ribs," has disappeared or at any rate become extremely reduced, and in which the pelvis slants backwards, all features which are the opposite of those characteristic of the Chelonia and Plesiosauria. The following diagram expresses what I regard as the probable phylogenetic relations of the orders of Reptiles with which we are at present acquainted :- MAMMALIA. AVES. III. Anomodontia. < a PLl as « w II. Cotylosauria. I. Pariosauria. \ XV. OrniUionauria. XVI. Squamata. XII. Emydosauria. XIV. Orthopoda. XIII. Dinosauria. VI. Acrosauria. V. Pelycosauria. VII. Thecodontia \ IV. Rhynchocephalia. X. Plesiosauria. IX. Placodontia. VIII. Chelonia. Labyrinthodontia Microsauria. BATRACHIA STEGOCEPHALA. For obvious reasons, I cannot accept the names Synapsida and Diapsida for the two phylogenetic series. I will designate the first subclass by the name Theromora of Cope, in a restricted sense, and suggest for the second that of Herpetomorpha. The Theromora may be divided into three orders, the Herpetomorpha into thirteen. |
