56 Prof. A. Macalister on the Myology 



The latlssimus clorsi arises from the lower dorsal spines 

 tlirougli the medium of the lumbar fascia from the lower five 

 ribs, and is inserted as usual into the inner bicipital lip of the 

 humerus. Meckel mentions that it is divided into two parts ; 

 but one of these is the pectoralis quartus described above. In 

 the Anteater the origin of this muscle is described as being 

 purely costal and fascial. In the Armadillo its origin is ex- 

 tensive and normal. It is not so closely connected to the teres 

 major in the Ai as in the Great and Two-toed Anteaters, in both 

 of which it is described as being closely joined to that muscle. 



The deltoid muscle is small, triangular, and not clearly 

 segmented ; it arises from the acromion process and from the 

 scapular spine, and is closely connected to the trapezius on the 

 one side, and to the great pectoral on the other ; its insertion is 

 into the middle fourth of the outer side of the humerus. Its 

 area of insertion is not so extensive as is stated by Meckel ; 

 but allowance may perhaps be made for the youth of the pre- 

 sent specimen. Meckel mentions that it gives off an accessory 

 head to the biceps, wdiich we did not tind in our specimen. 

 In the Armadillo the deltoid is divisible into acromial, clavi- 

 cular, and spinous or scapular parts, as described by Galton 

 and Meckel. In Orycterojpus it is likewise trifid according to 

 Cuvier and Galton, bifid according to Prof. Humphry. It is 

 also bifid in the Anteater. 



The supraspinatus muscle was normal in origin and inser- 

 tion, as is the case in Orycterojnis^ Myrmeco])}iaga^ Dasypus, 

 and others. The infraspinatus is likewise regular ; and the 

 teres minor is absent, or, if present, its germ is fused with the 

 infraspinatus. A true teres minor is present in the Armadillo, 

 Orycterope (Humphry, loc. cit. p. 300; Galton, p. 574), and 

 Anteater. Meckel, indeed, mentions a teres minor in the Ai, 

 but it seems to be the next muscle, and not a true teres 

 minor. 



Subscapulo-humeral, a small muscle on the subscapular 

 aspect of the long head of the triceps, arises from the upper 

 portion of the axillary margin close to the glenoid cavity, and 

 is inserted below the lesser humeral tuberosity. It is quite 

 separate, in the Ai, from the subscapularis. This muscle was 

 described by Wenzel Gruber (Abhandlung aus die mensch- 

 lichen und vergleichenden Anatomic : Petersburg, 1854, 

 p. 109), by Mr. Wood and myself as an anomaly in human 

 anatomy (Proc. Roy. Irish Acad. April 1866, and Med. Press 

 and Circular, vol. iii. p. 79). I have found it in many ani- 

 mals, as stated in my former paper, to which I have to add 

 the Tiger and the Ai. 



The subscapularis was normal, as was also the case in CJiO' 



