THE MANUS. [CHAP. 



truncated ends, set in a continuous rod of cartilage. In 

 this way a certain amount of flexibility and elasticity is 

 secured in the flipper, but beyond this there is no actual 

 motion between the various bones of which it is composed. 



The manus of the Right Whale (Balana mysticetus] is 

 comparatively short and very broad, having all five digits 

 present, and being also extended on the ulnar side by a 

 flattened cartilage projecting from the edge of the carpus, 

 representing the pisiform bone. In adult specimens there 

 are usually only three distinct ossifications in the carpus. 

 The numbers in the digits are respectively I. i, II. 4, 

 III. 5, IV. 4, and V. 3. In the Rorquals {Balanoptera} 

 the first digit is absent, and the manus is of an elongated 

 and narrow form. The carpus has five ossifications, and the 

 number of phalanges varies somewhat in different species. 

 In Megaptera^ the phalanges are both numerous and long, 

 producing the remarkable form of manus characteristic of 

 the genus. 



In the Odontocetes, the ossification of the skeleton of 

 the manus is usually more complete than in the Whalebone 

 Whales, the carpal bones generally coming in close contact 

 at their edges, and assuming a somewhat polygonal form. 

 The phalanges are also better ossified, often having epi- 

 physes at each extremity, and they are connected together 

 by imperfect synovial joints. They are always very much 

 flattened, and their extremities being truncated and their 

 sides nearly parallel, they are either square or oblong 

 in form. In size they gradually decrease to the end of 

 the digit, the last often consisting of minute nodules or 

 granules, so irregularly or imperfectly ossified, and so easily 

 lost in cleaning, that it is in many cases impossible, when 

 describing the skeleton of one of these animals, to give the 

 exact number of phalanges to each digit. 



