18 



THE VOYAGE OF H.M.S. CHALLENGER. 



The accompanying table shows the length of the lumbo-sacral portion of the vertebral 

 column of different species in inches. 



Length of Lumbo-Sacral Segment op Vertebeal Colcmn.i 



Coccygeal Vertehrce. 



The caudal vertebrte, including the pygostyle, are eight in number. Each, with the 

 exception of the pygostyle, possesses a body, transverse and spinous processes. The bodies 

 are cylindrical in form, and their articular surfaces are concave. Each, with the 

 exceptions of the first and second, develops a rough nodular hypapophysis. These 

 processes are larger in the case of the last two or three vertebrae (including the pygostyle) 

 than in the others, and are mostly bifid at their extremities. 



The length of the transverse 2)yoccsses is equal to that of the bodies of the vertebrse 

 from which they spring. They are quadrilateral in form, and much flattened from above 

 downwards. As a rule the transverse processes of the first, and sometimes of the second 

 caudal vertebra, abut against the pelvic bones. 



The spinous processes are of large size. Those of the first, second, third, and fourth 

 vertebrae are bifid at their extremities, while those of the remaining three are simply 

 tubercular. They diminish in size from the first to the last. The pygostyle in Eudyptes 

 chrysocome measures one and a-half inches in length, and is triangular in section. 

 The lateral surfaces are convex from above downwards, while the lower is deeply 

 grooved longitudinally. According to Gervais and Alix,^ it consists in the embryo of 

 nine separate vertebrae. These authors enumerate only seven coccygeal vertebras, but in 

 Eudyptes chrysocome, on which these observations were made, I found eight. This number 

 also agrees with Eeid's ^ observations on the Patagonian Penguin. It is possible, although 

 nowhere stated, that MM. Gervais and Alix include the first caudal vertebra of the 



' In this tahle the breadth of the spine of the last dorsal, although fused with those of the lumbo-sacral vertebrse, 

 is not included in the measurements. 



2 Osteologie et Myologie des Manchots. 

 - Proc. Zool. Soc, 1835, p. 134. 



