ANATOMY OF MEGAPTERA LONGIMANA. 19 



2!^-, the latter that of the 64-feet-long B. musculus reduced 

 to Jg. 



Form. — The paddle of B. musculus presents, on the radial 

 border, only a gentle elevation opposite the distal end of the 

 radius, and thence sweeps in an even convexity to the tip. On 

 the ulnar side there is the considerable but gradual elevation 

 at the pisiform cartilage, and thence to the tip the even con- 

 cavity, giving the clean-cut edges and elegant form, smooth- 

 edged, curved, tapering, and pointed, of the paddle in that finner 

 (fig. 13), in striking contrast with that of Megaptera (fig. 6). 

 It is seen from that figure that most of the projections on the 

 radial border of the paddle of Megaptera are caused by the great 

 size and lateral projection of the cartilages of the digital joints. 

 These nodes are nine in number, and the reason for that num- 

 ber is seen. Node No. 1, that nearest the body, most abrupt on 

 the proximal side, very great, and the longest, is caused by the 

 projection of the end of the radius, and by the sloping away 

 from it of the radial border of the carpus and of the index 

 metacarpal. Nos. 2 and 3 are caused by the nodes of the index 

 digit. No. 2 more gradual and not so high as No. 3. No. 4, a 

 great hump-like projection, is caused by the expanded terminal 

 cartilage of the index digit and the ending of that digit. It 

 rises 4| inches beyond the general outline of the border, and is 

 most abrupt on the proximal slope. The hollow between it and 

 No. 3 is very marked, like that of a deep saddle. The remain- 

 ing five projections are caused successively by the now exposed 

 nodes of digit III. No. 5 is low but better marked than No. 

 2 ; Nos. 6, 7, and 8 are prominent, No. 7 the most so. The 

 well-marked hollows between are rather wider than the mounds. 

 No. 9 is situated at about 9 to 10 inches from the tip, is gradual 

 and less prominent. 



On the ulnar border there is the usual great but gradual 

 elevation over the pisiform cartilage, its highest part a little 

 proximal to the radial elevation. The border then sweeps on, 

 gently concave, without undulation till about 20 inches from 

 the tip, where two true projections occur, caused by the 6th and 

 7th nodes of digit IV. The second of these rises li inch, 

 and is opposite the 8th prominence on the radial border. 

 Between it and the tip occur four or five little undulations, 



