o/'Cyclothurus didactylus. 249 



second division of the deltoid, a pouch being thus formed the 

 concavity of which looked upward. The muscle was inserted 

 along the whole length of the inner edge of the shaft of the 

 humerus, the lowest fibres terminating at a ridge situated 

 above the inner condyle. Cuvier evidently regarded this 

 muscle as a portion of the triceps. Those fibres which arose 

 from the scapular spine he held to be an accessory factor 

 (" extcnseur venant de I'epine de I'omoplate," pi. 257. fig. 1). 

 If the whole of the muscle is not to be regarded as the teres 

 major, that portion, at any rate, which arises from the costa 

 of the scapula must be considered as such, while those fibres 

 which arise from the scapular spine may be regarded as a 

 portion of the triceps which has fallen short of its insertion. 



No part of this enormous muscle reached the olecranon, no 

 fibres, in fact, passing below the foramen in the humerus which 

 transmits the median vessels and nerve. 



Cuvier represents the teres major in the Two-toed Anteater 

 as a small muscle which becomes fused with the latissimus 

 dorsi before insertion (pi. 257. fig. 3). 



This muscle is stated by Meckel (Archiv, p. 42) to be " sehr 

 stark." Beside a humeral attachment similar to that just 

 described by me, a portion of the muscle is said to pass to the 

 olecranon, and thus to be adjutant to the extensor of the fore- 

 arm, as a factor of which muscle it is finally regarded by 

 Meckel. 



The muscle which I have termed teres major was supplied, 

 on the inner aspect of the arm, behind the tendon of the latis- 

 simus dorsi, by a nerve (subscapular?) given off" from the lower 

 of the two factors of the axillary nerve. 



Latissimus dorsi. A few fibres continued from the inner- 

 most edge of this muscle are joined, at a point where the 

 muscle divides into its humeral and dorso-epitrochlear por- 

 tions, by the outermost of the two slips into which the ventral 

 panniculus splits at its upper part. This compound slip joins 

 the inferior surface of those fibres of the pectoralis major which 

 are derived from its upper stratum, at their junction with the 

 terminal tendon. 



The above-described offset from the latissimus dorsi evi- 

 dently answers to a muscular " abnonnality " occasionally 

 found in man, and termed '' Achselbogen " by the German 

 anatomist Langer. It is, however, regarded by Prof. Maca- 

 lister {loc. cit. pp. 54, ^b) as a fourth pectoral muscle. 



Where the above-mentioned fibres diverge from the dorso- 

 epitrochlear factor, a slip arose from the internal surface of the 

 muscle, and soon passed into a stout fiat tendon, which, pass- 

 ing between the median and circumflex vessels and nerves, 



