OSTEOLOGY OF THE PENGUINS. 397 



For the vertebral column, we find all the bones of the cervical 

 and dorsal regions freely movable upon one another; those of 

 the pelvic sacrum fuse most solidly into one piece, and to this 

 the pelvic bones proper do not coosify as solidly as they do in 

 many other birds ; the skeleton of the tail is greatly elongated, 

 and finished off with a pygostyle of very unusual length. In 

 the cervical series there are invariably 15 vertebrae in all 

 Penguins known to me. The 1.3th of these often has the 

 pleurapophyses showing faint rib sutures; on the 14th a pair 

 ■of free ribs is always found ; and those on the 15th invariably 

 possess articulated epipleural appendages. A very remarkable 

 character is seen in the transverse processes of the 13th and 

 14th vertebrae, for these are elongated, and curl dorsad in a 

 very striking manner, especially in Ajjtenodytes pennantii and 

 Spheniscus demersus. 



The carotid arches are always open, and commonly com- 

 mencing with the 6th vertebra^, pass to include the 9th or 10th. 

 Apparently non-pneumatic, these cervical vertebrae are short 

 and wide, with conspicuously developed processes ; complete 

 lateral canals (3rd to 13th included); and when articulated 

 m sitio, form in all the species a pronounced double sigmoid 



curve thus 



\ 



For the dorsal region, the vertebrae are articulated with each 

 other in a way to insure the greatest amount of strength con- 

 sistent with the maximum degree of mobility, while in all the 

 species the neural and haemal spines, as well as the transverse 

 processes, are uncommonly broad and strong. 



There are six dorsal vertebrae in Aptenodytcs, Sj^heniscus, and 

 JJudyptes, or in all the genera I have examined, and some of 

 these may be opisthocoelous in character. They each and all 

 support long, rather slender, true vertebral ribs, that connect 

 with the sternum by long, slender, sweeping and curved costal 

 ribs, after the manner of certain Auks, The epipleural append- 

 ofjes are large, flat, and elongated, and articulate with the ribs 

 to which they belong. The last pair have them only in a rudi- 

 mentary form in Sphenisctcs minor and >S'. demersus, but they 

 •are present upon that pair in A. penna7itii, in which species 



