hemispherical smaller one, which is separated from the larger 

 portion nearly as distinctly as in dolphins, and contains the 

 cochlea. Three of the four deep holes which separate these 

 two portions of the labyrinth, are pierced at the bottom of 

 the trefoil-shaped large one. They serve for the admission 

 of nerves. The tympanum or drum is formed by a thick 

 bony shell, curved inwards longitudinally, so as to resemble 

 the whorl of an univalve mollusc; and to form thus a wide canal 

 where the Eustachian tube takes its origin. Behind, this 

 canal is closed, and assumes a somewhat bilobed form at the 

 place where it becomes confluent with the posterior part of 

 the labyrinth, by means of a rugose bony apophyse, to which 

 the suspending cartilage is attached. 



OF THE SPINAL COLUMN. 



The spinal column in our specimen consists altogether of 

 forty-four vertebrae, i. e., if we consider the cervical verte- 

 brae to be only two. But these in fact are seven, the first or 

 atlas being free, and the other six* much compressed, being 

 anchylosed together, as is manifested by their distinct ridges, 

 which Cuvier long since pointed out in his London 

 Skeleton, Oss. Foss. pi. SS, fig. 13. 



The dorsal vertebrae, or those to which the ribs are 

 attached, are ten in number, having the vertical spinous 

 processes inclined backwards, and increasing in length from 

 the first to the last. They have also short transverse pro- 



♦ In tlie genus Hyperoodo7i and most of tlie Delphinid^ all the seven cervical 

 vertebrae are soldered together, which occurs likewise in the true whales. But 

 in the bottlenosed dolphin, as well as the dolphin of the Ganges, (Platanista 

 Gangetica of Cuvier), it is stated by Cuvier that all the cervical vertebrae are 

 free ! "What is singular is, that in the Korquals, at least in the Cape Rorqual, 

 the only cervical vertebrae soldered together are the axis and its following 

 one ; all the rest being quite free. In the order of Cetacea it is to be observed 

 that the cervical vertebrae vary much in structure. For instance, Daubenton 

 and Cuvier both state that the manati has only six such vertebrae. 



