428 



ANATOMY OF VERTEBRATES. 



that of the Orang : the third is very small, and represents the 

 cuneiforme : the pisiforme is separated from it by the junction of 

 the unciforme with the ulna : the unciforme supports the rudiment 

 of the fifth digit and part of that of the fourth: the magnum 

 supports part of the fourth finger and a great part of the third : 

 the trapezoides is moved to the interspace between the third and 

 second digits, but principally supports the latter. The metacarpal 

 of the first digit, in D. Tursio, fig. 290, I, supports one small 

 phalanx : the larger metacarpal of the second digit, ii, supports 

 seven phalanges : that of the third, iii, supports five phalanges ; 

 the metacarpal of the fourth, iv, two phalanges : the fifth, v, 

 is represented only by a rudimental metacarpal bone. 



In the Grampuses, Porpoises, and other Delphinidce, the second 

 and third digits are also the longest, with the excessive number 

 of phalanges. The fifth metacarpal articulates nearer to the anti- 

 brachium than the others do. In both the Porpoise and Grampus, 

 e. g., it is attached to the ulnar border of the carpus, is broader 

 than long, and supports one or two stumpy phalanges : the 

 first metacarpal is short and slender, but its base is on the 

 distal border of the carpus. In the Hi/peroodo7i there are three 

 carpals in the proximal row, and a second row of four small 

 ossicles in the fibro-cartilaginous matrix. The metacarpal of the 

 poUex supports one phalanx : those of the second and third digits 

 have each five phalanges : the fourth me- 

 tacarpal has three ; the fifth, which is the 

 shortest of all, has two phalanges. In theC«- 

 chalots and Ziphius, the fourth digit more 

 nearly equals the third in length : in BalcBna 

 mysticetus, fig. 159, IV, it rather exceeds the 

 second, ib. ii, and, like it, the metacarpal 

 supports three phalanges ; the third meta- 

 carpal, ib. Ill, having four phalanges, and 

 the fifth, V, two : the first digit is the 

 shortest, and consists of metacarpal only. 

 In Platanista the first metacarpal has two 

 phalanges, the other four each support four 

 phalanges, the fingers being of nearly equal 

 length, and more divergent than usual, 

 supporting a fin correspondingly expanded 

 to its free truncate end. 

 In some Piked AYhales {BalcBnoptera) the first digit is obsolete, 

 tlie third and fourth much longer than the second and fifth. In 

 Bed. lomjimana {Kyphohalcuna, Esch.), the third and fourth each 



290 



Bones of rcctoral lin, Dclphinus. 



