48 PROFESSOR STRUTHERS. 



was nearly as bulky as the common tendon of the two flexors. 

 The flexor carpi ulnaris is, therefore, as far as I could judge, as 

 fully developed in Megaptera as in B. musculus, relatively to the 

 flexors of the digits more so. It will serve to give increased 

 resistance to this soft part of the paddle. 



Flexor digitorum ulnaris. — This muscle resembles the same 

 muscle in B. musculus, but is very much smaller. Belly, length 

 5 inches, flesh continued 1 inch farther on deep aspect of tendon ; 

 greatest breadth, at middle, 1 h inch ; thickness, | to ^ inch ; 

 figure triangular. Origin from the ulna, doubtful if any fibres 

 come so far forwards as from the humerus. Belly lies obliquely 

 on the slope to the interosseous space. Tendon 14 inches 

 before it joins tendon of radial flexor. Lies on interosseous 

 slope of ulna and then for 5 or G inches sunk in the interosseous 

 space, finally getting into same sheath as radial flexor. Tendon 

 is about I inch broad, and about twice the bulk of that of an 

 average human plantaris muscle. 



Flexor digitorinn radialis. — Is about three times the size of 

 the last muscle, but smaller than in B. musculus. Arises from 

 the ulna as well as from the radius, beginning about 4 inches 

 later than the ulnar flexor, length of belly 8 inches, the flesh 

 running on the deep aspect of the tendon for 3 or 4 inches more. 

 The tendon runs up in the belly like a septum, rendering 

 it bipenniform, as in B. musculus. Bulk of belly about that of 

 two thick fingers. Tendon, after 4 inches of pure tendon, in all 

 16 inches from the origin of the muscle, receives the tendon 

 of the last muscle. This is at about the junction of the 

 middle and distal thirds of the fore-arm. Tendon lies deep 

 in the interosseous hollow, flattened sideways, about -|- inch 

 thick. 



Dissection. — Each of these muscles lies in a sheath of fibrous 

 tissue, i to ^ inch thick. The fleshy fibres partly arise from 

 this sheath. The tendons are not very loose within the sheath, 

 as if they did not move far. From their interosseous position 

 and the great thickness of the sheaths these tendons, and fleshy 

 parts too, might readily be overlooked. The first structure come 

 upon, on slitting up the very thick aponeurosis of the fore-arm, on 

 the flexor aspect, is a great nerve, as large as the forefinger, sur- 

 rounded by loose areolar tissue within its sheath. Also in a 



