Mackintosh — On the Myology of the Genus Bradypiis. 521 
insertion into the seventh and eighth, and considers it to be an exten- 
sion backwards of scalenus. 
Latissimus dorsi ("4 + panniculus carnosus) arises from the lumbar 
fascia over the lower dorsal spines, and from the fifth to the twelfth 
ribs (lower five, Professor Macalister), and has the usual insertion into 
the humerus, quite separate from teres major. 
Deltoid ("22) is not at all divisible, and has a very extensive origin 
from the acromion process, half the scapular spine, coracoid, and a 
small part of the clavicle ; it is inserted into nearly the entire upper 
half of the humerus, giving olf an accessory head to the biceps, as is 
noticed by Meckel, a condition which was not found by Professors 
Macalister or Humphry. The former anatomist describes the deltoid 
as taking origin from the acromion, and entire scapular spine, and 
being inserted into the middle fourth of the humerus. In Professor 
Humphry's specimen the origin was coracoidal closely connected with 
the biceps. 
Supraspinatus (-1) is normal in all, with a very wide tendinous 
attachment to the capsule of the shoulder joint in Arctopithecus. 
Infraspinatus ('1) is also normal in all, and teres minor is absent 
in our specimen and that of Professor Macalister, who observes that the 
muscle described under that name by Meckel seems to be a subscapulo- 
humeral ; Professor Humphry, however, says that it was quite dis- 
tinct and separate from the deltoid in his specimen. 
Subscapulohumeralis ("04) arises from the upper part of the axillary 
margin of the scapula, and is inserted below the lesser tuberosity of 
the humerus. Professor Humphry considers this to be the hindmost 
of the three parts into which subscapularis was divisible. 
Subscapularis (-22) is normal in all, with five tendinous intersections 
in our specimen. 
Teres major is (°16) large, normal, and separate from the latissimus 
dorsi in all, and has a surface insertion in Arctopithecus. 
Coracobrachialis (-05) has a tendinous origin and insertion, the 
latter into the second fourth (upper fourth, or nearly upper third, Pro- 
fessor Macalister) of the humerus. 
Biceps is a very remarkable muscle, consisting of humeral ('14) 
and scapular ('04) portions. The former arises by a flat tendon from 
the lesser tuberosity of the humerus, and from the ridge below it, also 
by a slip from the deltoid (biceps coracoidalis of Professor Humphry); 
and one from the deltoidal crest below that muscle ; its long tendon 
passes between these two parts, lying on the bone (quite separate from 
the scapular portion and anterior to it), to be inserted by a strong 
tendon into the tubercle of the radius in all. The deltoidal head is 
described by Meckel, but no trace of it existed in Professor Macalister's 
specimen. Scapular biceps arises from the top of the glenoid ligament, 
and continues tendinous as far as the lower border of the insertion of 
the deltoid, here it becomes fleshy and is inserted musculo-tendinously 
into the ulna, on the same level as, but anterior to, brachialis anticus. 
Yery nearly the same arrangement exists in B. tridactylus. 
