Vlll INTROUrCTIOX. 



careful attention to minute and apparently trivial details to determine 

 the affinities of isolated bones. Prof. Alphonse Milne-Edwards, who 

 was the first in this field of research, has, however, clearly shown 

 that such specimens in most cases afibrd characters sufficient to 

 enable us to arrive at a more or less close approximation to the 

 affinities of their former owners, although the difficulty of such 

 determinations increases as we recede in time. It is, however, im- 

 possible to give precise definitions of the various groups based 

 on such osoteolgical features ; and the only way in which such 

 features can be made available for classification is by treating the 

 more important of them in considerable detail. It will be found 

 in the sequel that in some groups special attention is directed to 

 certain parts of the skeleton, either upon the ground of their showing 

 the most important structural characteristics, or that they are more 

 generally preserved in a fossil condition, while in other groups, for 

 the same reasons, more particular notice is taken of other bones. 



After the text was in the printers' hands the writer found that 

 the determination of the respective coracoids of Cnemiornis and Ap- 

 tornis (see pp. 99 and 153) had already been made by Mr. H. 0. 

 Forbes in the ' Trans. New-Zealand Inst.' vol. xxii. p. 545 (1890). 



As in the other Catalogues of Fossil Vertebrates, specimens form- 

 ing part of Collections of more or less historic interest are entered 

 with the name of the Collection to which they respectively belong. 

 The following list gives particulars relating to the Collections 

 mentioned : — 



Bowtrhank Collection. — Purchased in 1865 from the late Dr. J. S. 

 liowerbank, of Highbury. 



Brady Collection. — Comprises a few species from the Pleistocene 

 of Ilford, purchased in 1878 from the late Sir Antonio Brady, of 

 Stratford. 



Bravard Collection. — Includes a large series of bird-remains from 

 the French Tertiaries purchased in 1852 from the late M. Bravard, 

 and also a few from the Pleistocene of South America purchased in 

 1854. 



Cauiley Collection.— Specimens from the Siwalik Hills of India, 

 presented in 1840 by the late Col. Sir Proby T. Cautley, K.C.B. 



Clcmssen Collection. — Comprises a few specimens from the Pleis- 

 tecene deposits of South America, purchased in 1845 from the late 

 M. Claussen. 



Croizet Collection. — Purchased in ] 848 from the late Abbe Croizet ; 

 includes specimens from the French Tertiaries. 



Cun)iin</ton Collection. — Purchased in 1875 from Mr. W. Cun- 

 nington, of Devize.-;. 



