ODONTOENITHES. 

 :p a. :r t i . 



O D O N T O LC^l, 



(Plates I-XX.) 



CHAPTER I. 



THE SKULL OF HESPERORNIS. 



(Plates I-II and XX.) 

 It is most fortunate for science that Hesperomis regalis — with a single 

 exception, the oldest bird known — should now be represented by remains 

 as complete as any fossil skeleton yet discovered, even in the later 

 formations. Nearly all the bones of the specimens obtained were almost 

 as perfect as in life, when first found in the matrix ; although the more 

 delicate parts were sometimes unavoidably broken in removal, and 

 occasionally small fragments were lost. Many of the bones were near 

 their natural position when discovered, and in such cases a special effort 

 was made to preserve this position, or retain a record of it, by drawings. 

 However difficult such a method of collecting really is, in the region 

 explored, its importance will be fully appreciated by anatomists. 



Various remains belonging to about fifty different individuals of 

 Jlesperornis are now in the Museum of Yale College, and the most 

 important of them are described in the present memoir. 



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