538 • MR. J. C. GALTON ON DASYPUS SEXCINCTUS. 



the forearm, between the two prongs of the forked tendon of insertion of the latter 

 muscle, to be inserted into a fossa in the nlna, overhung by the coronoid process of this 

 bone, a little anterior to, and to the outer side of, the insertion of the ulnar division of 

 the tendon of the biceps. 



This muscle, according to Meckel, is, in the Anteater, fused with the olecranal 

 division of the biceps. Its insertion is, in the Platypus, according to the same author, 

 confined to the radius 1 . 



The brachieus interims is, according to B,app, absent in M. tamandua 2 . 



Triceps. — A well-developed, and, apparently, very powerful muscle, made up of the 

 following factors, which will be separately ennmerated ; 



1. Scapular.— This, the largest portion of the muscle, arises from the inferior, or lesser, 



spine of the scapula, along the whole of its extent ; and after proceeding some distance 



on its course, joins the external humeral head of the muscle, and, in company with this, 



is inserted into the olecranon process, and becomes also continuous wdth the fascia on 



i he outer side of the arm and forearm. Another element of this portion of the muscle, 



which is probably the representative of the "long" head of human-anatomy language, 



takes origin from the lower, or axillary, border of the scapula, from a projecting ridge 



situated just posterior to the neck of the bone, by a thick tendon, invested externally 



with muscular tissue. It has a uniform breadth, and runs in close company with the 



preceding element of the scapular factor, to share the same insertion, fusing with it near 

 its termination. 



This factor is inserted in the posterior edge of the olecranon, overlapping the insertion 

 of the internal humeral head. This part of the muscle is, moreover, continuous with the 

 fascia covering the elbow. 



2. External humeral factor.— A strong fleshy slip, which arises by a thin tendon, 

 encircling about half the circumference of the neck of the humerus— namely, that space 

 which intervenes between the two tuberosities on the posterior and outer aspect of the 

 bone. This tendon completely covers the fleshy fibres of the origin of the brachialis 

 anticus, and is, moreover, overlapped on its outer aspect by those fibres of the teres minor 

 which pass across to their insertion below the external tuberosity of the humerus. This 

 factor takes origin also from nearly the whole length of the posterior edge of the ridge 

 running from the above tuberosity to the deltoid trochanter. About one-third of the 

 distance between its origin and insertion, it fuses with the two most posterior divisions 

 of the deltoid at their point of insertion into the great trochanter of the humerus, and 

 arches over that portion of the brachialis anticus which lies in the channel between the 

 above process and the origin of the extensor carpi radialis. After this point it becomes 

 continuous by its outer edge with the fascia of the arm. Its inner edge, after proceeding 



about two-thirds of the distance between origin and insertion, fuses with the scapular 

 factor of the muscle. 



hiL Int 7 al h " meral '- A somewhat ^nder slip arising along the inner aspect of the 

 1™ fr om ^mediately below the insertion of the subscapulars to almost the lower 

 exticmity of the posterior boundary of the supracondyloid foramen. It is inserted into 



Op. tit. p. 525. 



Op. cit. p. 48. 



