150 ME. E. T. NEWTON ON THE EEMAINS OF A 



very numerous iu the locality in early Eocene times, and lead us to expect that, when 

 these same marshy beds are exposed in other places, more specimens will be discovered. 



III. — Comparison of the Croydon Bird-remains with other Eocene Birds. 



About forty species of birds have been described from Eocene strata in different parts 

 of Europe and America, but only a few are sufficiently near to our Croydon fossils to 

 render a comparison with them desirable. The only British bird which makes any 

 approach in size towards these from Croydon is the Dasornis londinensis of Prof, (now 

 Sir Bichard) Owen (Trans. Zool. Soc. vol. vii. p. 123, 1872) ; but as this genus is only 

 represented by a portion of a skull from the London Clay of Sheppey, no comparison 

 with it can be made. 



M. Hebert, in the year 1855 (' Comptes Rendus,' vol. xl. p. 579), gave the name of 

 Gastornis parisiensis to a large avian tibio-tarsus from the "Argile Plastique" of 

 Meudon, to which attention had been called by M. Constant Prevost a short time 

 before ('Comptes Rendus,' vol. xl. p. 554). Subsequently portions of a femur, another 

 tibio-tarsus, a fibula, and some phalanges were found. In 1856 Sir R. Owen discussed 

 the affinities of this bird before the Geological Society (Quart. Journ. Geol. Soc. vol. xii. 

 p. 204); and M. Milne-Edwards also gave a very full description of these remains in 

 the 'Oiseaux Fossiles ' (vol. i. p. 165, 1867-68). 



Dr. Victor Lemoine, in his ' Recherches sur les Oiseaux Fossiles des Environs de 

 Reims' (part i. 1878, part ii. 1881), has described a number of birds' bones from Lower 

 Eocene strata, some of which are believed to belong to two new species of Gastornis — 

 one, equalling in size the Gastornis parisiensis, is called Gastornis edwardsi, and the 

 other, which is much smaller, is called Gastornis minor. Of the larger species a good 

 part of the skeleton has been found, including parts of the skull, vertebras, pelvis, 

 femur, tibio-tarsus, tarso-metatarsus, and toe-bones, also a coracoid, a fragment of a 

 sternum, and parts of the wing. (See also Bull. Soc. Geol. Fr. ser. 3, vol. xiii. p. 412.) 



M. L. Dollo has described the distal half of a large femur from the Lower Eocene 

 (Landinien) of Mesvin, near Mons (Bull, du Mus. Roy. Belg. vol. ii. p. 297, 1883), 

 which he refers to Gastornis edwardsii. 



The name of Diatryma gigantea has been given by Prof. E. D. Cope to a large avian 

 tarso-metatarsus from the Eocene strata of New Mexico (Proc. Ac. Nat. Sci. Philad. 

 ser. 3, vol. vi. p. 10, 1876), which is said to resemble Gastornis. 



The Croydon birds' remains are evidently more nearly related to Gastornis than to 

 any other known form, and with this genus it is now proposed to compare them. 



A plaster cast of the original tibio-tarsus of Gastornis parisiensis from Meudon is 

 preserved in the British Museum of Natural History at South Kensington, and the 

 bones from Croydon have been carefully compared with this, as well as with the 

 published descriptions and figures. When the Croydon tibio-tarsus (PI. XXVIII. 



