104 THE MYOLOGY OF THE RAVEN. 



posterior moiety of the belly of tliis muscle into two 

 portions, covered by separate sheaths of fascia, but in 

 the smaller and anterior division the fil;)res again come 

 together and are included in the same sheath. 



In the Apteryx this muscle has very much the same 

 origin and insertion that it has in the Eaven. Ac- 

 cording to Mivart it " is generally in Mammals much 

 as it is in the human sul)ject. It may be considerably 

 smaller, however (as in Cetaceans) ; and by a singuiar 

 exception it may (as in the Echidna) exclusively arise 

 from the external surface of the scapula " [Eleu. 

 Anat., p. 326). 



The subscapularis is a powerful rotary muscle of tLe 

 head of the humerus, and also an important auxiliaiy 

 in retaining that bone in its shallow facet, and 'prcr 

 venting displacement. 



66. The serratus 2:)arvus anticus ^ is a thin, flat musch 

 covering the outer parietes of the chest. It arises by 

 three rather extensive digitations from the outer surfaces 

 of the first free rib, and the next two succeeding ones 

 that connect with the sternum, above the origins of the 

 seri^atus tnagnus anticus and the thoraco-scapularis. 

 The fi.bres in a flat sheet of fascia pass upwards and back- 

 wards, to become inserted in the inferior margin of the 

 corresponding scapula, along a line to the outer side of 

 the insertion of the rhomboideus, as indicated in Fig. 8. 

 In the Penguins this is the largest of the muscles of the 

 scapula. 



In the Eaven at least, the levator sccqnilce, the 

 serratus parvus anticus, and the serratus magnus 

 anticus, all really belong to the same system or series, 



^ See footnotes and synonymy under muscles described in the 

 present work as the serratus magnus anticics and the thoraco- 

 scajmlaris (ISTos. 59 and 64). 



