338 TRANSACTIONS OF THE [OCT. 4, 



ternainates in a flat, tendinous lamella, which joins the tendon 

 of insertion of the Ento-pectoral along the caudal margin (PI. 

 XXX.. fig. 2). 



The tendon of the Entopectoral passes underneath that of the 

 Supraspinatus (PI. XXX., fig. 2; PI. XXXI., fig. 1) and ex- 

 pands into the cephalic and lateral portions of the humero- 

 scapular capsule, reaching the lateral humeral tuberosity and 

 covering the intra-capsular portion of the long tendon of the 

 Biceps. 



Main Tendon of Insertion of Ecto^^ectoral. 



After separating the abdomidal slip from the remainder of the 

 Ectopectoral — which can be accomplished without dividing 

 muscular fibres — the main tendon of insertion is seen folded on 

 itself (PI. XXXI., fig. 2) so as to form two lamella? of unequal 

 width, united caudad, open cephalad. The superficial lamella de- 

 rived from the cephalic and middle sternal origin of the muscle,ex- 

 tends from the lateral humeral tuberosity to the distal extrem- 

 ity of the lateral bicipital crest, overlapping cephalad the com- 

 bined insertion of the Entopectoral and abdominal portion of 

 Ectopectoral. 



The caudal sternal fibres of the muscle, passing successively 

 underneath the caudal mai-gin of the preceding, form the deeper 

 lamella, only one-half as wide as the superficial, the direction of 

 the tendon fibres intersecting obliquely. 



The analysis of the entire pectoral insertion, therefore, results 

 in establishing the following five divisions or layers, proceeding 

 from the deep to the superficial parts : 



1. Axillary arch tendon from Latissimus dorsi (PI. XXIX.). 



2. Tendon of Entopectoral and abdominal portion of Ecto- 

 pectoral, constituting a separate layer (PI. XXX., fig. 2). 



3. Fibres from the caudal sternal origin of the Ectopectoral 

 develop the deep lamella of the main Pectoral tendon (PI. 

 XXXI., fig. 2). 



Continuous with this along the caudal border is 



4. The superficial lamella of the Ectopectoi'al insertion, de- 

 rived from the muscular fibres which arise from the cephalic and 

 middle sternal attachment (PI. XXXI., fig. 2). 



5. On the superficial aspect of this tendon the clavicular por- 

 tion of the Ectopectoral finds its insertion, closely fused with 

 the adjacent margin of the Deltoid (PI. XXXII., fig. 1). 



The published descriptions of the anatomy of the Pectoral 

 group in the Lemuroidea do not agree in some main points with 

 the conditions found in our species. 



Murie and Mivart (1, p. 25), describing the Ectopectoral of 

 Lemur catta, distinguish the three portions of the muscle, in re- 

 spect to their origin, as clavicular, sternal and abdominal. 



