THE BIRDS OF HAITI AND THE DOMINICAN REPUBLIC 361 



lateral extension continuing to opposite the base of the knee where 

 each tract was suddenly restricted and continued as a narrowed line 

 down the side of the abdomen, the two converging finally to meet 

 the circle of feathers surrounding the anal prominence. 



The arrangement of the shoulder muscles was typical of that of 

 the oscinine Passeriformes according to present knowledge. The 

 M. propatagialis longus (fig. 2) was free from the shoulder for a 

 short distance only before becoming tendinous. It received a very 

 slender slip from the M. cucullaris. The M. propatagialis brevis was 

 moderately strong in form, elliptically elongate and pointed. From 

 the slightly prolonged lower point came a slender tendon that 

 passed down and attached to the tendon of the M. extensor meta- 

 carpi radialis longus, and then separating again passed inward to 

 insert on the ectepicondylar process of the humerus. 



On the upper arm the M. deltoideus major brevis was strong and 

 heavy extending practically the full length of the humerus to insert 

 on the ectepicondylar process. The M. deltoideus major longus was 

 likewise long and strong. It narrowed somewhat below, but did 

 not become tendinous. It inserted in fleshy fasciae at the base of 

 the ectepicondylar prominence behind the insertion of the tendon 

 of the brevis portion of this muscle. 



The M. latissimus dorsi was double, both anterior and posterior 

 portions being present, of which the latter was slightly the stronger. 

 The two were separated in origin as usual but converged rapidly and 

 met immediately after passing out over the scapula. At the point 

 where the two passed free from the M. trapezius toward their attach- 

 ment on the humerus the anterior portion overlapped the posterior 

 and continued partly superimposed upon it. 



In the Tyrannidae the arrangement of these muscles is different. 

 In Tolmarchus gabbii, a tyrannine form, the M. propatagialis brevis 

 is more moderate in development, extending only half way down 

 the humerus, with the lower end decidedly blunt. The slender 

 tendon extends from the outer margin of the blunt termination and 

 is attached below in the usual manner to the tendon of the M. extensor 

 metacarpi radialis longus. The two tendons attach finally to the 

 ectepicondylar process very near one another the point of attachment 

 of the brevis lying above and external to the other. The disparity 

 in size between the two tendons beyond their point of attachment 

 is marked, that of the brevis being only about one third the bulk of 

 the other. The other shoulder muscles exhibit marked differences 

 from the condition described in Lawrencia nana. The M. deltoideus 

 major brevis is quite heavy but extends only three-fifths of the 

 length of the humerus to insert on the humeral shaft. There is no 

 tendon proceeding down from it to the ectepicondylar process. The 

 M. deltoideus major longus also is partly aborted as it thins out, 



