44 PROFESSOR STRUTHERS. 



a series of alternating great elevations and hollows, continued 

 smoothly from one to the other, and mostly fitted to each other. 

 The nodes are not generally opposite the middle of the hollows. 

 That could only well be with equal length of the bones of 

 neighbouring digits. The hollows are about twice the length 

 of the nodes, and the node may be received into the proximal, 

 or the middle, or the distal part of the hollow. 



The alternation is accomplished simply thus. By the greater 

 length of the metacarpal bone and also of the first phalanx of 

 digit III. the nodes of that digit are projected just beyond the 

 nodes of the two neighbouring digits, which, again, are about 

 opposite each other. The result is that the nodes of digit III. 

 are received into the proximal part of the hollow of the succeed- 

 ing phalanx of the neighbouring digits, and that the nodes of 

 the latter are received into the distal part of the hollow of the 

 preceding bone of digit III. Then, by the shortness of the 

 metacarpal of digit V., the adaptations between it and digit IV. 

 are in like manner accomplished. If digits II. to V. of the 

 human hand be placed together, it will be seen that there is the 

 same arrangement of the phalanges in them, more evident if 

 the observer will imagine the middle finger drawn forward a 

 little. In these other fin-whales the method by which the 

 nodes are rendered not opposite each other is the same, but 

 the result is less striking in them than in Megaptera, owing to 

 the comparative shortness of the bones and to the lesser 

 size of the node compared with the breadth of the phalanges 

 in them. 



The following are the exact positions of the nodes in Megap- 

 tera. In digit III. their position opposite the proximal part of 

 the hollow of the succeeding bone continues till the next last 

 node, the 6th, is reached, which is seen to lie in the distal half 

 of the hollow, owing to the shortness of the 6th bone of 

 digit IV. The 5th node may be said to occupy the entire 

 hollow of the 6th bone of digit IV. In digit IV., correspond- 

 ingly, the fitting of the nodes against the distal part of the 

 hollows of digit III., is continued on the first five ; the 6th lies 

 in the whole hollow, and the 7th more on the proximal side of 

 the hollow. Of digit II. the first node lies in the distal third of 

 the hollow of the metacarpal, the second just past the middle 



