ANATOMY OF MEGAPTERA LONGIMANA. 23 



render its border still more straight. In my 64-feet-long B. 

 musculus there was but a narrow strip of cartilage along 

 most of the border, enlarging into a triangular plate behind 

 and before, covering the more curved parts of the posterior 

 and anterior ends of the bone, and forming a nearly straight 

 upper border, with a little curving down at the posterior 

 angle, the cartilage at which was the largest. D'Alton's 

 figure of the scapula of Megaptera (Taf. iv. fig. /.) is the likest 

 to the scapula of this Megaptera of any of the figures given ; 

 but in his figure the anterior border is longer than the posterior, 

 and the anterior angle is blunted. On the anterior border in 

 my Megaptera, below the junction of its lower and middle 

 thirds, there is a gentle elevation, 3 to 4 inches long, with a 

 rough summit, shown only in the figure of Megaptera Lalandii 

 of Van Beneden and Gervais (PL IX. fig. 4), scarcely to be 

 recognised in B. musculus. 



The Upper Border. When these scapulae are placed in 

 pairs on the floor, standing on their glenoid cavities, various 

 differential characters come into view ; the relation is seen 

 of the different thicknesses and curvatures of the upper 

 border to the stronger and thinner parts of the body and 

 to the curvatures of the surfaces. The much greater thick- 

 ness of the upper border and of the whole bone in Megaptera 

 is striking. In the 60|-feet-long B. musculus the thick parts 

 are, in front for 8 inches (increasing from J inch to 1 inch 

 forwards), the front half of that much bent down ; and behind 

 for 16 inches (increasing from f inch to 1J inch backwards), the 

 hinder three-fourths of that much bent down. These thick 

 parts appear as if incompletely ossified, as when denuded of 

 cartilage. The long (32 inches) intervening nearly straight 

 part of the border is thin, from \ to J inch, mostly J. These 

 thick fore and back parts are also somewhat bent outwards, 

 giving a moderate outward concavity to the border where each 

 of the two thick parts meets the intervening thin part, but the 

 general effect is a slight concavity outwards of the whole border. 

 The two thick parts are seen to be the ends of the anterior and 

 posterior beams of the scapula, the anterior beam strengthened 

 by the spine of the scapula running up to it at the anterior 

 angle. The same thick parts and curvatures are seen in the 



