MB. "W. H. FLOWER ON THE OSTEOLOGY OF THE SPEBM- WHALE. 361 



radiale, intermedium, and ulnare of Gegenbauer. The middle one is usually the 

 largest and most thoroughly ossified. In the genus Orca alone there is no ossification, 

 even in the adult animal, corresponding to the cuneiform. 



■1. The three bones of the distal row are generally represented by distinct ossifica- 

 tions in Hy^eroodoti, Beluga, and Monodon. These appear to correspond with the 

 trapezoid, magnum, and unciform of human anatomy. 



5. In most cases the bones of the distal row of the carpus are reduced to two, which 

 appear to correspond best with the trapezoid and unciform, the magnum being either 

 absent or amalgamated with the trapezoid. I here differ from Dr. Van Bambeke, who 

 considers that the two bones of the distal row represent the magnum and the trape- 

 zoid, the unciform beuig absent. My reasons are : — 



a. The magnum in mammals generally is a smaller and less important bone than the 

 unciform. 



h. In those animals in which the carpus approaches most nearly to that of the Cetacea 

 in configuration and functions, but retains all its elements distinct, as the Manatee, the 

 magnum and the trapezoid are particularly reduced, while the unciform is large, and 

 occupies the position of one of the well-developed bones of the cetacean carpus. 



c. In those Cetaceans in which all the bones of the second row are developed, and 

 can be distinctly recognized, as in Ilyiieroodon, the magnum is small. 



d. In the skeleton of a Beluga I have found the magnum present, while in the 

 carpus of another animal of the same species, otherwise completely ossified, its place 

 was occupied by cartilage. 



e. Whenever the magnum is present as a distinct bone, it is placed exactly above 

 the middle of the third metacarpal bone, and has a carpal bone on each side of it, 

 articulating with the second and fourth metacarpals respectively. In the Cetacea having 

 but two bones in the second row of the carpus, the middle of the proximal end of the 

 third metacarpal corresponds with the interval between these bones, which articulate 

 respectively chiefiy with the second and fourth metacarpals, each taking a portion of the 

 third. Sometimes this interval is so large as to suggest the absence of a bone. 



f. It is, however, not improbable that the bone which in general position corresponds 

 with the trapezoid, as it forms the chief support to the second metacarpal, may also 

 contain the representative of the magnum. This seems clearly to be the case in the 

 carpus of Micropteron sowerbyense, according to a sketch kindly sent me by Professor 

 Van Beneden, in which a single, transversely elongated bone corresponds to the bases 

 of both the second and third metacarpals. This view is also confirmed by the extremely 

 reduced condition of the trapezoid in the Manatee. 



6. The trapezium appears never to be present as a distinct bone, although the first 

 metacarpal so often assumes the characters and position of a carpal bone that it may 

 easily be taken for it. The rudimentary and simple cliaracter of the bones of the manus 

 (if the Cetacea is well illustrated by the difficulty of interpreting the nature of th(.' 



