ANATOMY OF MEGAPTERA LONGIMANA. 27 



in Megaptera by 30J oz., and in the measurement (that given 

 in the Table) is 1 inch higher and 1 inch longer than the left. 

 The right in the 50-feet-long B. musculus is 31 oz. heavier 

 than the left, and is J inch higher and J inch longer than the 

 left. The left in the B. borealis is the heavier, by 141 oz. against 

 135 for the right ; but the left has an additional piece behind, 

 giving it a length of 30 inches against 28 J for the right. 



5. THE HUMERUS. Viewed from the shoulder, the articular 

 surface of the head of the humerus seems more extensive 

 relatively than in the other finners. This is owing to the 

 articular surface in Megaptera advancing more than in them 

 towards the flexor aspect. Hence the head in Megaptera is 

 placed more on the end of the bone, although its projection to 

 the exterior aspect, and olecranon wards, is not less than in other 

 finners. The epiphysis of the head forms nearly a third of the 

 length of the bone. 



Where the articular cartilage of the head, and that of the 

 tuberosity, had lain, the rough appearance of the bone is very 

 striking ; perforated by numerous vascular apertures, admitting 

 a crow-quill or thick pin, the apertures surrounded by eleva- 

 tions, forming irregular prominences as thick as the end of a 

 little finger, and joining each other in a network, rendering the 

 whole area tubercular, pitted, and perforated. 



6. THE FORE-ARM. Besides by their greater length and thick- 

 ness, as compared with those of this 50-feet-long B. musculus, 

 as seen in Table I., the bones of the fore-arm in Megaptera 

 may be recognised by marked differences in form. This is 

 more strikingly seen by comparison with the paddle of my full- 

 grown B. musculus (this Journal, 1872), 65 to 66 feet long, the 

 paddle from head of humerus to tip 7 feet 8 inches, in which 

 the radius, omitting the epiphyses, has precisely the same 

 length as in this 40-feet-long Megaptera with a 12-feet-long 

 paddle. 1 



The radius of Megaptera is less bent, is narrower along the 



1 In connection with the description of the bones and joints reference may be 

 made to figure 6, showing the left paddle, flexor aspect, of this Megaptera 

 reduced to ^ T , in which I have endeavoured to represent all the parts with 

 exactness ; and, for comparison, to figure 13, showing the same aspect of the left 

 paddle of the 64-feet-long B. musculus, reduced to T V, also drawn by me from 

 nature. 



