ANCESTORS OF BIRDS. 3

It is unnecessary to discuss here the relationships of the birdhke reptiles, but, as the most convincing argument in support of the theory of the reptilian descent of birds, I present a restoration of the Archaeopteryx, the earliest known progenitor of the class Aves. This restoration is Fig. 1.— Restoration of the Archasopteryx, a toothed, reptilelike bird of the Jurassic period. (About '/s natural size.) based on an examination of previous restorations in con- nection with a study of the excellent plates which have been published of the fossils themselves.* Two speci- mens have been discovered ; one being now in the British Museum, the other in the Berlin Museum. They were both found in the lithographic slates of Solenhofen, in Bavaria, a formation of the Jurassic period, and, together, furnish the more important details of the structure of this reptilelike bird. This restoration, therefore, while doubtless inaccurate

• For recent papers on the Archaeopteryx

(Macmillan Co.), vols, v-viii. Natural Science