291 



Camper* states that the size of the tympanum is relatively smaller in 

 the Cachalots than in the Whalehone Whales. 



In the Baleenoptereeihe tympanic bones, according to Cuvier, are very 

 small in proportion to the head, and are equally convex at their inferior 

 surface. 



As none of the fossils in question have been found, in situ, with any 

 part of the cranium, their relative size to the animal cannot be judged 

 of; but in the specimens that have been least injured and waterworn, the 

 inferior surface shows the flattened or gently concavo-convex undula- 

 tion which characterizes the tympanic bone in the true Whales (Balance). 



1455. A fragment of bone, smooth on one side, and on the opposite showing a 



coarse cetaceous bony texture^ and petrified like the fossils from the red 

 crag. 



From Harwich Cliff, Essex. Hunterian. 



1456. A similar fragment, from the same locality. Hunterian. 



\457. A fragment of bone, smooth on both sides, but with a marginal fracture 

 displaying a coarse cetaceous bony texture : it is completely mineralized, 

 and in the condition of the fossils of the red crag. 



From Harwich Cliff, Essex. Hunterian. 



1458. Two similar fragments of bone, from the same locality. Hunterian. 



1459. A fragment of bone of a coarse cetaceous texture, petrified and in the 



condition of the fossils from the red crag. 



From Harwich Cliff, Essex. Hunterian. 



Order MARSUPIALIA. 



Genus Diprotodon. 



1460. The anterior extremity of the right ramus of the lower jaw of the Dipro- 

 todon australis, Owen, exhibiting the rough articular surface of the broad 

 and deep symphysis, the base of the large incisive tusk, the second and 



* Loc. cit, p. 108. 

 2 P 2 



