18L)U.] THE MYOLOGY Ob' TUB EUEXi'ATA. 327 



superficially to the others, while the spiaous fibres are inserted 

 highest and pass deep to the other two bundles. In those animals 

 ia which the clavicle is absent or rudiuieutary, the clavicular part 

 o£ the muscle is continuous with the ventral fibres of the trapezius 

 to form a ceplialo-humeral. Among the BradypodkUe, Bradypus 

 has the cephalo-humeral, acromial, and spinous parts closely 

 blended and inserted into the middle of the humerus (1, 3, 4). 

 lu two specimens (4, 5) a slip was given to the short head of the 

 biceps from the cephalo-humeral. In Choltepus the insertion 

 varied in two specimens — in one (10) the clavicular and acromial 

 portions were both inserted into the radius, while in another (8) 

 all three parts went to the deltoid tubercle. Among the Mi/rmeco- 

 phagidce, Mi/rmecop)haga (11, 12, 13) and Tamaadua (14, 16) have 

 each a cephalo-humeral and all three parts are mserced into the 

 middle of the humerus. In. Cyclothurus (17, 18, 19, 21) the 

 clavicular, spinous, and acromial parts are all inserted into 

 the humerus together, the two latter being apparently closely 

 fused. In the Dasypodidce the clavicular slip rises from the clavicle 

 in Dasypus {22^ 23), Tatusia (25, 26), and Ghlamydophorus (27, 2S), 

 and is always inserted into the deltoid tubercle on the humerus. 

 The acromial and spinous parts may or may not be separate. In 

 the Manidce the cephalo-humeral is well marked, the spinous and 

 acromial parts are more or less fused, and in several specimens 

 (29, 32, 33, 34) a separate bundle was traced from the spine 

 of the scapula to the triceps or supinator lougus. Macalister 

 expresses some doubt as to the nature of this slip ; but we have 

 been able to satisfy oui^selves, by tracing the circumflex nerve 

 into it, that it is a part of the deltoid. In the Orycteropjodidre 

 the clavicular portion is inserted into the radius with the biceps, 

 the other two parts passing to the deltoid ridge (35, 36, 37). 



Supra- and Infraspinati. — In all cases the supra- is consider- 

 ably larger than the infraspinatus. In Dasypus (22, 23) the latter 

 muscle rises between the two scapular spines. 



Teretes major et minor. — One of the great characteristics of all 

 members of the Edentate Order, with the sole exception of the 

 Myrmecophagidce, is the great development of the teres major. 

 In many of these animals there is a considerable ridge of bone 

 marking off the origin of the teretes from that of the infraspinatus. 

 Of this ridge, which is called the inferior scapular spine, we have 

 already written in connection with Dasypus. The teres minor in 

 most of the Order has been described as present. In some cases 

 it is described as being fused with the infraspinatus or subscapu- 

 hiris, but from our own experience of the Order we can quite 

 easily understand how two observers, in the instances in which 

 the muscle is not well marked, might readily differ in their 

 description of the same animal, so that we shall content ourselves 

 by saying that this muscle is usually a distinct entity throughout 

 the Edentata. 



Suhscapxdaris. — In the Bradypiodidin the bundle of fibres rising 

 from the axillary border of the scapula and obtaining an insertion 



22* 



