20 



PROFESSOR STRUTHERS. 



but they are not prominences with a solid foundation, merely 

 slight wavings of the soft parts. Digit V. causes no projection; 

 the prominence formed by the pisiform keeps the skin away 

 from the first two nodes of the digit, and its third node does 

 not project on the ulnar side. The border does not come near 

 digit IV. till opposite its last two nodes, which project very 

 sharply on the ulnar side, and thus cause the two ulriar pro- 

 minences above described. 



The prominences on the paddle of Megaptera are, therefore, 

 unlike those on the head, not dermal, but owing to the adapta- 

 tions of the bones and cartilages. Their presence in Megaptera 

 but not in B. musculus is owing to the very much greater 

 expansion of the digital cartilages in the former. On piercing 

 with the exploring needle at the prominences and between them, 

 along the radial border, cartilage or bone was reached at from 

 I to 1 inch from the surface. 



2. TABLE I. Measurements of the Pectoral Fin and its parts, 

 of the Megaptera longimana, and of the 5Q-feet-long 

 Balcenoptera musculus. 



1 The breadths of the paddle of this Megaptera at various parts were, as 

 follows, in inches : At 18 inches from the body, 23 ; at 30 inches from the body, 

 the broadest part, 32| ; at the middle, 24 ; at three-fourths from the body, 18 ; 

 at 12 inches from the tip, 12 inches. 



