1901.] ANATO\rY OF GRUIFORjM ]3IR1)S. ()41 



to be compared with a separated poi'tion of a doubled covaco- 

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

 origin to the scapula is very peculiar. The conditiou is of course 

 markedly apocentrie. 



Deltoides patagialis. — This muscle is relatively narrow in all 

 the Grruiformes, being most narrow in the Gruiuae and Psophiinse. 

 The tendons termed longus and hrevis arise from its distal extremity, 

 directly in the Eallidaj (text-fig. 77, L., hr.) in Otis and in Eury- 

 pyga ; or after a very short common tendon, as in Animus^ the 

 Dicholophidse, and Heliornis (text-fig. 7'S) ; or after a long common 

 tendon, as in the Gruinae and Psophiina^; or the muscle itself may 

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

 The existence or length of the 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 Cliunga and Cariama. With the exception of 

 Rliinochetus, 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 

 Rliinochetus, is undoubtedly apocentrie and approaches the extreme 

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

 shown to exist in the eutaxic Alcedinidas and in other modified 

 forms of birds. 



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

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

 Aramus, Cariama, Cliunga, and Oti^-, and in the latter two it is 

 bouud 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 the values of 

 these slight modifications. 



The brevis tendon displays the most simple condition in the 

 Gruinae, where it is a straight, wide band running down to the 

 tendinous portion of the extensor metacarpi radialis, without 

 complication of any kind. In many of the Eallidae 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 o by Piirbringer and the proximal 

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

 broad and rather diffuse, but at its insei'tion 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 

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

 extension. In the Psophiinae the condition of the tendon is 

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

 the insertion end with its proximal slip and median slip with a 

 fan-like extension is like the arrangement in A^mmus. In Cliunga 

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

 traces of the distal and median slips, of the fan, and of a proximal 

 slip (y of Fiirbringer) running in towards the elbow. The conditions 



