REPORT ON THE SPHENISCID.'E. 



19 



present description in the lumbo-sacral series. I have before adverted to the difficulty 

 in determining to which series that vertebra really belongs. 



The caudal vertebrae do not difTer much in different species. In Spheniscus demersus, 

 Spheniscus 'inagellanicus and Siiheniscus mendiculus there are nine caudal vertebrae, 

 while in every other species examined there are only eight. In Pygosceles the transverse 

 processes of the caudal vertebrae are relatively longer than in other species. In Pygosceles, 

 Spheniscus demersus, and Spheniscus inagellanicus hypapophyses are not developed in 

 connection with the first, second, third, or fourth caudal vertebrae. The transverse pro ■ 

 cesses of the first caudal vertebra of Pygosceles differ from those of other species, 

 inasmuch as they do not abut against the pelvic bones. 



The table shows the number of vertebrae possessed by every species of Penguin 

 examined, with the exception of Spheniscus demersus, Spheniscus magellanicus and 

 Spheniscus mendiculus, all of which possess an additional caudal vertebra. In these, 

 therefore, the total number of vertebrae is forty-three. 



Len^gth of Vertebral Column from Atlas to extremity op Pygosttle, in inches. 



Hudyptes ehrysocome, from Tristan, 



Eudyptes ehrysocome, from the Falklands, 



Eudyptes ehrysocome, from Kerguelen, 



Eudyptes clirysolophus, 



Spheniscus demersus, 



Sphetiiscus magellanieus, 



Spheniscus mendiculus, 



Spheniscus minor, 



Pygosceles tceniatus, 



Aptenodytes longirostris, 



i4 



is" 



20 



IH 



15 



12| 



21 



26^ 



The Eibs. 



The vertebral segments of the ribs are ten in number in every species of Penguin, 

 and increase in length from the first to the ninth. Gervais and Alix^ figure only nine 

 in Eudyptes ehrysocome, and Reid ' found the same number of ribs in the Patagonian 

 Penguin. The diversity of statement between these authors and myself is explicable 

 by the fact that the tenth vertebral rib is extremely slender in every species, and that 

 its proximal extremity does not articulate with the vertebral column. In consequence of 

 its small size and its want of attachment to the vertebral column this rib is apt to be 



' Ost^ologie des Manchots, pi. xvi. figs. 4 and 5. 

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



