rice- President's Address. 11 



races. The action of these muscles is supposed to tell upon 

 the femoral shaft much in the same way as the temporal 

 muscles affect the formation of a longitudinal ridge upon the 

 cranium of a dog. 



In the buttock, the great size of the ghdeus maximus 

 muscle is a concomitant of the erect attitude, and, moreover, 

 this muscle is regarded as the chief cause of that peculiar 

 flattening of the upper third of the femoral shaft to which 

 Turner was the first to direct attention, and to which 

 Manouvrier gave the name of platymerie, a condition 

 which is most characteristio of the femora of the Maoris. 

 Apart from this condition, however, the inclusion and fusion 

 of the agitator caudm muscle with the gluteus maximus — a 

 condition which is indicated in the course followed by cer- 

 tain cutaneous nerves through the lower part of the gluteus 

 maximus — may be regarded as a direct proof of an evolu- 

 tionary process. Of similar interest and value is the absence 

 of the scansorius muscle from the human buttock, since this 

 muscle is intimately connected with the movements of the 

 thigh in climbing. 



In the upper limb, many muscles provide evidence of 

 evolution, either in the repetition of historic forms, or in the 

 appearance of characters which are progressive. Among the 

 group of muscles by which the upper limb is attached to the 

 trunk, outstanding variations are not very common, and they 

 have apparently acquired a fair degree of stability. Occa- 

 sionally, however, the insertion of the pectoralis minor is 

 carried beyond the coracoid process of the scapula to the 

 upper part of the humerus, which, in some animals, is its 

 normal attachment. For this reason, the coraco-humeral 

 ligament of the shoulder-joint is believed to represent the 

 detached and isolated portion of the original tendon of in- 

 sertion. 



The coraco-hrachialis muscle, which attaches the humerus 

 to the scapula, is one of very great interest. The type of this 

 muscle in mammals is one whose coracoid attachment is 

 single, but whose humeral or brachial end presents three 

 separate and distinct insertions into the humerus, viz., (1) 

 into the humeral shaft above the tendon of the teres major; 



