MUSCLES OF THE EORE LIMB 79 



in others the pectoral is divided into a superficial and deeper 

 layer. In many ' Ciconiiformes ' this is the case. The 

 pectoral, in all birds except the ratites, gives off one or two 

 branches to the patagium. The branch has been termed 

 the pectoralis propatagialix. There are either two separate 

 muscles split off from the surface of the pectoral (as in Nisus), 

 the tendon of one going to the tendon of the tensor patagii 

 longus, that of the other to the tensor patagii brevis ; or 

 (Podargits] there is but one muscle which divides into two 

 tendons ; or the origins of the two tendons are separate, one 

 of them commencing with a special muscle, the other arising 

 as a tendon from the surface of the pectoralis ; or both may 

 be tendinous in origin. Finally, there is in tinamous and 

 gallinaceous birds (some) a special ' propatagialis posticus,' 

 joining with its tendon that of the other muscle. The 

 pectoralis abdominalis, totally absent in nearly all ratites, in 

 storks, various hawks, &c., is divisible into two parts, of 

 which one or other is sometimes wanting. The pars posterior 

 springs from the pelvis and adjacent fascia ; it ends in front 

 freely or comes into more or less close relations with the pars 

 anterior. In Anseres, for example, the two form one con- 

 tinuous band of muscle, their boundaries being simply marked 

 by a slight tendinous inscription. The pars anterior arises 

 from the skin close to the termination of the last, or is, as 

 already mentioned, continuous with it ; it generally ends upon 

 the humerus, near or in common with the insertion of the 

 main part of the pectoral. In a few birds (quite remote 

 from each other in the system, Pelecanus, Chauna, Cathartes) 

 the terminal tendon is lost in the axillary region ; a more 

 remarkable modification, possibly of classificatory importance, 

 is described later in Crypturus. In a variety of birds there 

 is a slip from this muscle to the metapatagium. 



Latissim/us Dorsi. This muscle is divided by FURBRIN- 

 GEK into three sections - 



(1) L. d. (ulterior. 



(2) L. d. posterior. 



(3) L. d. metapatagialis mid dorso-cutaneus. 



The first-named muscle is totally wanting in Apterijx and 



