698 



MR. T. MAITNEBS-SMITH ON THE 



[Dec. 4, 



and are inserted into the radius at the junction of the upper and 

 middle thirds. Between the two heads of origin a muscle is 

 inserted which is probabl)"^ the pectoralis minor. Only one head 

 is present in Echidna (Mivart, loc. cit,). 



Fig. 1. 



Muscles op Arm. 



a. Brachialis anticus. 



(3. Triceps, 

 brachialis. 



y. Infra-spinatus. 

 6. Deltoid. 



S. Epicoraeo- 



Coraeo-bracliialis. — Two portions of the typical coraco-brachialis 

 are present. A longer superficial portion, arising in conjunction 

 with inner (larger) head of biceps from sternal portion of coracoid ; 

 it is inserted into the bar of bone bridging over the well-marked 

 supra-condyloid foramen. The deeper portion arises from coracoid 

 and whole of epieoracoid, just below and in front of glenoid 

 cavity ; it is inserted into the upper third of the humerus. The 

 tw^o portions are entirely distinct, the tendon of latissimus dorsi 

 separating them from below ; both parts are supplied by a branch 

 from the median nerve. The first portion only is called by Coues 

 coraco-brachialis ; the second he describes as epicoraco-bracbialis ; 

 the same two portions are found in Echidna (IMivart, loc. cit.). 

 There is a distinct epicoraco-brachialis, but in addition two 

 portions of the typical coraco-brachialis are present, as described 

 above. 



Brachialis anticus. — Arises from humerus, its origin extending 

 as high as the head of the bone. The muscle is inserted into the 

 upper fourth of the shaft of the ulna. 



Triceps. — This is a very large, strong muscle, consisting of four 



