418 Othniel Charles Marsh. 



The acquisition of a unique specimen of Pterodactyl from 

 the lithographic slates of Bavaria enabled him to supply the 

 long sought information regarding the wing and caudal mem- 

 branes. Notices of a number of new species of fossil Croco- 

 diles, Lizards, and Turtles, complete this survey of his work on 

 the Reptilia. 



Practically, most of the present knowledge of extinct bird- 

 life in America is contained in Marsh's publications, which 

 include descriptions of numerous species, ranging from the 

 Jurassic to the Post-Pliocene. Unquestionably, the one dis- 

 covery which is always foremost in men's minds in a considera- 

 tion of his work is the determination of an extinct order of 

 birds possessed with teeth. The study of the Dinosaurs and 

 Toothed Birds showed that one by one characters considered 

 as avian were likewise present in reptiles, and that many rep- 

 tilian characters were present in these primitive birds ; so that 

 at the end there did not seem much else besides feathers to 

 distinguish them. Marsh's investigation of fossil birds led to 

 the publication, in 1880, of his first monograph, "Odontor- 

 nithes : a Monograph on the Extinct Toothed Birds of North 

 America." In this volume, he carefully figured and described 

 all the known types, and presented complete restorations of the 

 two leading genera, Hesperomis and Ichthyornis. He con- 

 cluded that birds most nearly resemble some of the small 

 Dinosaurs from the American Jurassic, and that both classes 

 originated at least as far back as the Trias or late Paleozoic, 

 in some sauropsid type. 



A discovery which rivaled that of the Toothed Birds, 

 although not so wholly his, was the genealogy of the Horse. 

 Huxley and Kovalevski traced the equine branch through the 

 Pliocene to the Upper Miocene in Europe, but the true and 

 remote ancestry remained unsolved until the American types 

 were described by Marsh. He showed that a primitive and 

 diminutive polydactyl horse existed in the Lower Eocene, and 

 that from this type, by gradual and progressive change through 

 successive horizons of the Eocene, Miocene and Pliocene, 

 there had been evolved all the intermediate stages leading to 

 the modern horse. 



Next in importance and interest should be noticed the series 

 of papers culminating in the monograph of the Dinocerata, 



