1901.] 



ANATOMY OF ©EUirORM BIKDS. 



037 



division throughout the greater part o£ the extent of the muscle, 

 and, save in Gcdlimda phcenieurus and Porzana Carolina, they are 

 actually in continuity. The posterior part, corresponding to the 

 posterior division in most birds, is enormously strong and large, 

 and its origin has spread distally until it has reached a considerable 

 portion of the ilium and the musculature of the thigh. At the 

 insertion, tbe fleshy and broad insertion of the anterior portion 

 (text-fig. 74, L.A.) is superficial, and its proximal edge is in contact 



Text-fig. 74. 



Text-fig. 75. 



Shoulder-muscles oi Rcdlm longirostris. Shoulder-muscles oi Psophia obscura. 

 Musculature of right shoulder, external ^iew. 



2. Tendon of supra-coracoideus A.S. Anconajus scapidaris, cut short, 

 and ill text-fig. 75, reflected. S.A. Scapuli-humeralis anterior. S.P. Scapidi- 

 hiuueralis posterior. S. Espausor secundariorum. L.P. Latissimus clorsi 

 posterior. L.P. A. Slip of lat. dorsi post, to ancona^us scapularis. L.A. 

 Latissimus dorsi anterior. A.H. Aucoukus humeralis. S. C. Sub-scapuli- 

 coracoideus. 



3. Humeral anchor of anconaeus. 4- Humeral insertion of lat. dorsi ant. 

 The tendinous areas are dotted. 



and partly fused with the tendinous iusertiouof the posterior division 

 (text-fig. 74, 4^). The latter runs to the humerus, in close associa- 

 tion with the humeral anchor of the anconseus scapularis (text- 

 fig. 74, 3). It also sends proximally a remai'kable muscular slip 

 (text-fig. 74, L.P.A.) which is fused with the chief origin of the 

 anconseus scapularis. The condition of this muscle ofiiers three 

 points of special note. The great size and backward extension of 

 the muscle with its iliac origin are certainly apocentric. The fusion 

 of the two divisions along a great part of their course, from 

 origin to insertion, is possibly archecentric, and brings to mind 

 the single latissimus dorsi of Apteryx, a condition possibly arche- 

 centric for Aves, and to be compared with the single muscle in 

 Reptiles. The muscular attachment to the anconaeus of the inser- 

 tion of the posterior division possibly is archecentric : in any case 

 the only parallel to it with which 1 am acquainted is the similar 

 condition described by Fiirbringer in the case of Casuarius. 



In the Grruidse the conditions differ. In the Gruinge the two 

 Piioc. ZooL. Soc— 19U1, Vol. II. No. XLII. 42 



