ANATOMY OF MEGAPTERA LONGIMANA. 41 



each bone in Megaptera and in the 50-feet-long B. musculus, 

 give interesting results, read across and read down each column. 

 Reading across, it is seen that, in each of these whales, both the 

 breadth and thickness of the metacarpal bones, and of the 

 corresponding range of phalanges, diminish progressively from 

 digit III. to digit V., with the single exception of the meta- 

 carpal of digit V. which is J inch broader than that of digit IV. 

 In B. musculus the metacarpal of digit II. is likewise inch 

 broader than that of digit III., and they are of the same thick- 

 ness. In Megaptera the metacarpal of digit II. is seen to be 

 greatly more robust than that of digit III., exceeding it in 

 breadth by a half, in thickness by about a fifth. 



Reading down the columns, it is seen that, in B. musculus, 

 both the breadth and the thickness diminish progressively 

 onwards, the only exception being that in digit III. its 2nd and 

 3rd bones have the same thickness, and its 3rd and 4th bones 

 the same breadth. In Megaptera the exceptions to progressive 

 diminution distally are in digit III., that the 3rd bone is the 

 broadest (| inch broader than the 2nd, and 1 inch broader than 

 the metacarpal) and that the 4th bone has the same breadth as 

 the 2nd ; in digit IV., that the 2nd and 3rd bones have the 

 same thickness, and the 3rd and 4th bones the same breadth. 



Comparing the breadth with the thickness, irrespective of 

 size, reading across each range, it is seen in B. musculus, that, 

 from radial to ulnar side of the paddle, there is a proportionate 

 diminution of the thickness, giving a progressive flattening of 

 form from digit II. to digit V.; less marked from digit II. to 

 digit III., well-marked at digit IV., and very marked at digit 

 V.; and it is seen to be more marked as we read down the 

 columns. The only exception is on the metacarpal bone of 

 digit III., the thickness of which is only J inch less than the 

 breadth, while it is f less on the metacarpal of digit II. In 

 Megaptera there is not the same progressive flattening from the 

 radial to the ulnar side of the paddle. Reading across the 

 range, the bones that are thickest in proportion to their breadth 

 are the 2nd of digit II., the 1st of digit III., and the 4th and 

 5th of digit IV. The bones of digit V. have a more flattened 

 form than the others in the range, but their length compared 

 with their breadth renders this less striking to the eye. 



