76 



MR. A. SANDERS ON THE 



[Jan. 6, 



backward and ventrad to the base of the tuberosity of the humerus, 

 extending beyond the insertion of the last. 



Fig. 2. 



Muscles on the inner aspect of the arm. X 3. 



The supraspinatus corresponds to the muscle named by Mr. 

 Mivart epicoraco-humeral in Iguana, and subclavius in Chamceleon 

 parsonii. The infraspinatus does not appear to be represented in 

 Iguana, but might correspond to one of the suprascapulars in 

 Chamceleon. Teres minor corresponds to infraspinatus in Iguana, 

 but is not found in Chamceleon. In my two former papers I took 

 the liberty of differing from Mr. Mivart in the interpretation of 

 these three muscles, and explained my reasons for so doing ; but 

 perhaps it will save the trouble of referring to those memoirs, if I 

 briefly recapitulate those reasons in the present place. First, as to 

 the insertions, they are all inserted on the outer side of the 

 humerus, or close to it, at a point which corresponds to the greater 

 tuberosity ; these insertions occur in the following order, viz. the 

 supraspinatus nearest the head of the bone, the infraspinatus next, and 

 the teres minor* furthest off — an arrangement which closely agrees 

 with that found in the human subject. Next, with regard to the origins 

 of these muscles : supraspinatus arises from the coracoid bone together 



* In a lizard, however, which I have recently dissected, a species of the sub- 

 genus Tropidolopisma, this muscle ends in a tendon which winds round the 

 humerus to be inserted c'ose to the head of the bone, quite on the inner side, 

 being covered by the internal head of the triceps. 



