AYES. 87 



processes of bone being doubtless originally covered by Table-case 

 similar elevations of the horny beak, which would act like 13 - 

 teeth in dealing with the slippery prey. This bird was 



Fig. 83. — Skull and lower jaw of Odontopteryx tottapica, with bony denticles 

 on jaws, from the London Clay of i Sheppey; two-thirds nat. size. 

 (Table-caseil3.) 



probably related to the living gannets. Prophaethon resembles 

 a modern frigate bird, but has relatively larger bind legs. 

 Like the other fossils of the London Clay, these birds indicate 

 a subtropical climate in the south of England at the time 

 when they lived here. 



From the London Clay there is also part of a large 

 skull named Dasomis londiniensis by Owen, who thought 

 it might perhaps belong to a Eatite bird like the ostrich. 

 More satisfactory remains of a large running bird, Gastornis, 

 from the Lower Eocene of England, France, and Belgium, 

 suggest affinities with the geese rather than with the 

 ostriches. 



The earliest of all true and typical birds hitherto dis- 

 covered, are represented in Table-case 13 by a few bones of 

 Enaliornis from the Cambridge Greensand (Upper Cretaceous) 

 and by vertebra, a pelvis, and limb-bones, with plaster casts 

 of other bones, of Hesperomis from the Chalk of Kansas, 

 U.S.A. The vertebrae with saddle-shaped ends are especially 

 well preserved. These fossils seem to belong to swimming 

 birds like the existing divers (Colymbus) ; and the larger 

 bones from Kansas indicate a species H. regalis (Fig. 84), 

 which would measure from three to four feet in height. A 

 large drawing of a skeleton restored by the discoverer, 

 Professor 0. C. Marsh, is framed near the window. Hesper- 

 omis has teeth in a groove in each jaw, though the extremity 

 of its upper jaw is toothless, and would probably be covered 

 with the usual horny beak. The bird must have been flight- 

 less, as indicated by its flattened breast-bone (sternum). A 



