64 Appendix. 



the temor patagii brevis, whicli courses parallel witb the humerus, not distant from that bone, 

 to the muscles and fasciae of the forearm. In the Eamphastinae, Capitouinae, and Picinae, where 

 this muscle is less complicated than in any other birds, it arises, as is generally the case, from 

 the apex of the upper of the two processes at the scapular extremity of the furcula, as well as 

 by a small special slip from the superficial fibres of the pectoralis major muscle, which diiferentiates 

 itself off from the main muscle near the upper part of its inserted extremity. Tiie comparatively 

 insignificant triangular or compound fleshy belly thus formed, with its apex directed towards the 

 elbow, terminates in a cylindrical tendon, which, included Iietween the layers of the fibro-cutaneous 

 patagium, takes a straight course to its insertion into the axially-running tendon of origin of 

 the extensor metacarpi radialis longus of Schcipss, at a short distance from the tubercle on the 

 humerus whence'the muscle springs. 



As a result of this disposition, when the forearm is half-flexed, the tendon of the tensor 

 patagii hrevis is seen to enter the substance of the fibrous origin of the extensor met. racl. longus, 

 and at right angles. This arrangement without any additions is characteristic of the Picariae, 

 as defined by myself to include the three sub-families above referred to, and them only. 



Among the Passeres a slight, but easily recognizable, difference in the manner of insertion 

 of the muscle obtains. The similarly single cylindroid tendon runs from the muscular belly, 

 which has its origin at the shoulder, as above described, to the upper margin of the extensor 

 met. rad. longus muscle, at an exactly similar spot : it does not, however, simply blend with 

 the fibrous origin of that muscle ; it becomes attached to it at the spot indicated, and then 

 (again considering the forearm as half bent upon the humerus) runs back independently to be 

 attached to the base of the tubercle of origin of the extensor met. rad. longus, slightly 

 below that muscle's .springiug-point. As a consequence of this arrangement there are two 

 tendons to be seen running to one spot (that on the upper margin of the extensor met. rad. 

 longus, where the tendon of the tensor meets it) from two points, one the apex of the tubercle 

 on the humerus above referred to, and the other, the depression at its base. These tendons 

 therefore converge as they leave the elbow, having at first an appreciable interval between them, 

 which is gradually diminished as they approach, although they remain quite free from one another, 

 that of the tensor being superficial. 



I have had the opportunity of looking at this muscle in nearly 150 species of Passerine 

 birds, belonging to nearly all the most important sections, including, among the more noteworthy 

 genera — Struthidea, Heteralocha, Dicrurus, ProstJiemadera, Ifelanocoiyj^ha, Strepera, Menura, 

 Atrichia, Pitta, Rupicola, Lipaugus, Tyrannus, ChasmorhjncMts, Pipra, Tityra, lladrostomiis, 

 Cotinga, Furnarius, Picolaptes, ThamnopJiiliis, Grallaria, Pteroptochus, Hylactes, Psarisomtts and 

 SerUophus. 



The only apparent exceptions I have found are the following. In Pteroptochus alhicolUs 

 and in Llylactes megapodius the muscular fibres of the extensor met. rad. longus almost surround 

 and enclose the tendons in question. Such being the case, the arrangement does not at first 

 sight appear typically Passerine. Nevertheless, upon removing or pushing to one side these 

 covering fibres, the two tendons are seen arranged exactly as in other members of the order. 



In Menura supei-ba and in Atrichia rufescens, feeble-winged birds again, the arrangement 

 is not typical, and the disposition of the parts is almost exactly as in the Pici, as above described. 



