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towards the outer part of the coracoid. The preserved extremities of the 

 femur and tibia have the same conformation and relative size in the fossil 

 as in the existing Cathartes. In this genus, nevertheless, there is a 

 deeper depression on the outer surface of the sternum external to the co- 

 racoid groove, than in the fossil, but this difference is less marked in some 

 of the large Vulturidse. The fossil moreover indicates a smaller species 

 of Vulturine birds than is known to exist in the present day, and it pro- 

 bably belonged to a distinct subgenus. The name Lithornis has, there- 

 fore, been proposed for it with the specific appellation vulturinus. 



From the Eocene tertiary formation called the ' London Clay' at the 

 Isle of Sheppey, Kent. Hunterian* . 



Order CURSORES (Struthious or Wingless Birds). 



Genus Didus. 



1551. The cast of the head of the Dodo (Didus ineptus, Linn.). The head of 

 this extinct bird is remarkable for its large size in proportion to the 

 entire bird, and for certain peculiarities of form ; as, for example, the 

 great breadth of the cranium compared with its length, the great depth of 

 the beak compared with its breadth, and the sudden elevation of the frontal 

 region above the root of the beak. The cranium forms rather more than 

 one-fourth of the entire length of the skull. The occipital region is 

 broad and appears flat ; but part of the skull may have been here destroyed 

 in the original process of stuffing the bird. The contour of the temporal 

 depressions may be traced upon the sides of the cranium, separated above 

 by an interspace of two inches and nine lines : the orbits are compara- 

 tively small, wide apart, the interorbital space being three inches across : 

 the outer apertures of the ears are situated rather more than an inch be- 



* Of the sixteen specimens referred to the Class of Birds in the original Hunterian Manuscript 

 Catalogue of Fossils, every one belongs to the Class Reptilia, and the greater part to the genus Ptero- 

 dactylus. The specimen above described is not included in that Catalogue. 



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