1901.] anatomy or i.i:nrniiM BIEDS, <'>41 



to be compared with a separated portion of a doubled eoraco- 

 humeral-radial division of tbe biceps, but the extension of the 

 origin to tbe scapula is very peculiar. The condition is of course 

 markedly apocentric. 



Deltaides patagialis. — This muscle is relatively narrow in all 

 the Gruiformes, being most narrow in the Gruinae and Psophiina?. 

 Tbe tendons termed longus and brews arise from its distal extremity, 

 directly in tbe Rallidae (text-tig. 77, L., Jr.) in Otis and in Eury- 

 p'j'ja ; or after a very sbort common tendon, as in Aramus, tbe 

 Dieholophidao, and Heliornis (text-fig. 78); or after a long common 

 tendon, as in the Gruinse and Psophiinae; or the muscle itself may 

 fork into peaks for the two tendons, as in Rhinochetus (text-fig. 76). 

 The existence or length of tbe common tendon seems correlated 

 with the size of the bird or of the wing, and to be of minor 

 importance; the conditions vary in individuals and in forms so 

 closely allied as Chunga and Curiam a. With the exception of 

 Rhinochetus, all the members of the group may be taken as displaying 

 the muscle in an archecentric condition. The peaked condition 

 suggested in some of the Eallidse, and fully exhibited in the eutaxic 

 Rhinochetus, is undoubtedly apocentric and approaches the extreme 

 apocentricity of a completely divided muscle, a condition that T have 

 shown to exist in tbe eutaxic Alcedinidse and in other modified 

 forms of birds. 



The longus tendon is single in most of the Gruiformes (text- 

 figs. 76, 77, 78, L.), but is doubled in the distal elastic portion in 

 Aramus, Oariama, Chunga, and Otis, and in tbe latter two it is 

 bound down to the brevis tendon by a forearm anchor near where 

 the brevis is inserted to the fascia over the extensor metacarpi 

 radialis. 1 have not the materials to estimate tbe values of 

 these slight modifications. 



The brevis tendon displays the most simple condition in the 

 Gruinse, where it is a straight, wide band running down to tbe 

 tendinous portion of the extensor metacarpi radialis, without 

 complication of any kind. In many of tbe Eallidse the condition is 

 similar (text-fig. 77, br.), but the tendon is rounder and more sharply 

 separated from the fasciae of the patagial membrane, while in other 

 members of the family the insertion end shows signs of differen- 

 tiation into the distal slip termed a by Fiirbringer and the proximal 

 slip termed y by the same authority. In Aramus the tendon is 

 broad and rather diffuse, but at its insertion it divides into a well- 

 marked distal slip (a) and a diffuse median slip (/3), which is inserted 

 to the extensor tendon and passes in addition over that towards 

 tbe ulnar edge of the forearm to form a well-marked fan-shaped 

 extension. In the Psophiina; the condition of Hie tendon is 

 rounder and better separated from the fascia of tbe patagium, but 

 the insertion end with its proximal slip and median slip with :i 

 fan-like extension is like tbe arrangement in AramuSi In Chutufa 

 and Oariama the tendon is broad and diffuse, but distally shows 



i races of tbe distal and median -lips, of t be fan, and of a proximal 

 slip (y of Fiirbringer I ri tint ii o_r in towards I be elbow . The comlit ions 



