MR. W. H. FLOWEK ON THE OSTEOLOGY OF THE SPEKM- WHALE. 



359 



Dimensions of the Bones of the Arm. 



Tasraanian 

 skeleton. 



Humenis. 



Length 



Ereadth (vertical, or from the radial to the I 

 ulnar border) of head J 



Breadth at narrowest part 



Breadth at lower end 



Thickness at head 



Thickness at middle 



Radius. 



Length (between middle of each extremity 1 

 without epiphysis) J 



Breadth at upper end 



Breadth at middle 



Breadth at lower end 



Ulna. 



Length 



Breadth at upper end, including olecranon . . . . 



Breadth at middle 



Breadth at lower end 



Greatest width of interosseous space 



Tasraanian, 

 No. 1. 



Tasraanian. 

 No. 2. 



inches. 

 19i 



8| 





7| 



12| 

 10 



9i 



2 



inches. 

 22| 



9 



7| 

 114 



8i 

 4i 



15i 



n 



14 

 12 



5 



9 



2| 



inches. 



181 



12 



111 



101 



5| 



Yorkshire. 



inches. 

 20| 



134 



7| 

 Gi 



121 

 12 

 4| 



Caith- 



inches. 

 20 



7-1 



'2 



10| 



13i 



12 



11 



5 



8| 

 2i 



Paris. 



inches, 



174 



Hi 



5| 



IQi 



10 



5 



The carpus (PL LXI. fig. 1) is very remarkable on account of its width and short- 

 ness, the bones of which it is composed being so extended laterally as to appear almost 

 as if in a single row. As in most of the Toothed Whales*, ossification of the carpal 

 elements advances more rapidly than in the Whalebone-Whales ; and in the older speci- 

 mens the contiguous surfaces of the bones are brought into close apposition. In the 

 younger individuals each bone is surrounded, except on its smooth free (dorsal and 

 palmar) surfaces, by a layer of cartilage; and consequently its exterior presents the 

 peculiar and characteristic appearance described at p. 326. Moreover, in many cases, a 

 kind of epiphysial ossification has taken place in this cartilage, so that the bones are 

 surrounded by a more or less complete case of thin osseous matter, which appears 

 ultimately to unite with them (see PI. LXI. fig. 4). This mode of ossification of the 

 carpal bones, by a peripheral as well as a central nucleus, is, I believe, peculiar to the 

 Cachalot. It has occurred to a much greater extent in the carpus of the entire 

 skeleton than in the detached limb figured at PI. LXI. fig. 1 ; indeed, in the latter, the 

 peripheral ossifications were so small and so slightly adapted to the contiguous surfaces, 

 that, their attachments having been lost during maceration, they could not be replaced 

 with certainty, and so do not appear in the figure. 



All the specimens agree in the number and relative position of the carpal elements. 

 Besides a bone projecting freely from the ulnar side of the carpus, probably correspond- 



* Orca is an exception. 



