360 MR. W. H. FLOWER- ON THE OSTEOLOGY OF THE SPERM-WHALE. 



ing to the pisiform *, they are five in number, differing little from each other, either in 

 size or form. Although, as before said, they are so extended as to appear almost to 

 form a single row, it may be readily seen that the central bone and that placed at 

 eitlier extremity really belong to what is ordinarily considered the proximal row of the 

 carpus, while the two others constitute its distal row, thus conforming to what may be 

 called the typical form of the Cetacean cai-pus. 



The determination of the homologies of the carpal bones of the Cetacea with those 

 of other Mammalia is beset with difficulties, and has consequently led to some differ- 

 ences of opinion among those anatomists who have attempted it. The most recent essay 

 on this subject is that of Dr. Van Bambekef , who, however, laboured under the great 

 disadvantage of having very insufficient materials at his command. I have been able to 

 examine a considerably larger number of specimens, comprising nearly all the known 

 genera, but must still admit that the determination of homologies of parts from the 

 comparison of adult, or nearly adult, individuals is but provisional, and awaits, for its 

 verification, the opportunity of tracing their development through the earliest stages 

 of existence. 



The results of these observations on the cai-pal bones in the Odontoceti (to which 

 group it is alone necessary to refer to illustrate the anatomy of the Cachalot) may be 

 stated in the following propositions. It may be premised that every species appears 

 liable to certain individual variations, and that sometimes the different sides of the same 

 animal are not precisely alike either in the arrangement or even the number of the 

 carpal ossifications. Such cases have often afforded a valuable clue to the identifica- 

 tion of particular bones. 



1. The pisiform bone is represented in Belphinus tiirsio by a small ossification on the 

 ulnar border of the carpus, and attached to the lower end of the ulna itself. In Inia a 

 similar ossification projects from the same border of the carpus, but on a level with the 

 bones of the second row J. In Physeter it occupies a more normal position. These are 

 the only instances that I have met with of the occurrence of this element in an ossified 

 state in any of the Toothed Whales, though it must be admitted that, as it is a part so 

 liable to be removed in cleaning the skeleton, it may be more frequently developed than 

 our prepared specimens would indicate. 



2. Excluding the above, the carpus of the Odontoceti appears never to consist of 

 more than six bones, three belonging to the proximal and three to the distal row. 



3. The three bones of the proximal row are constant, and may easily be identified as 

 corresponding to the scaphoid, semilunar, and cuneiform of anthropotomy, or the 



* This was wanting in the limb figured, having probably been removed during the partial process of cleaning 

 it had undergone before I received it. The bone represented in the figure is taken from the hand of another 

 Bpcfimen, in which it was still in situ. 



t " Sur le Squelette de I'extremite anterieurc des Cetaces." Mem. de TAcad. Roy. de Belgique, t. xviii. 1865. 



± As in the C'helonians. 



