MUSCULAR SYSTEM OF AVES. 



85 



35 



ever, entirely wanting. In the Struthious and short-winged sea 

 birds, in which the dorsal vertebrae are unfettered by anchylosis, 

 these muscles are more fleshy and 

 distinct, most so in the Apteryx, 

 and will here be described as seen 

 in that bird.^ 



The sacro-lumbalis is the most 

 external or lateral of the muscles 

 of the back, and extends from the 

 anterior border of the ilium to the 

 penultimate cervical vertebra. It 

 arises by short tendinous and car- 

 neous fibres from the outer half of 

 the anterior margin of the ilium, 

 and by a succession of long, strong, 

 and flattened tendons from the an- 

 gles of the fifth and fourth ribs, 

 and from the diapophyses of the 

 third, second, and first dorsal verte- 

 bra3 ; also by a shorter tendon from 

 that of the last cervical vertebra; 

 these latter origins represent the 

 musculi accessorii ad sacro-liimba- 

 lem ; to bring them into view, the 

 external maro-in of the sacro-lum- 

 balis must be raised. These acces- 

 sory tendons run obliquely forward, 

 expanding as they proceed, and are 

 lost in the under surface of the 

 muscle. It is inserted by a fleshy 

 fasciculus with very short tendinous 

 fibres into the angle of the sixth 

 rib, and by a series of correspond- 

 ing fasciculi, which become progressively longer and more ten- 

 dinous, into the angles of the fifth, fourth, third and second 

 ribs, and into the parapophyses of the first dorsal and last two 

 cervical vertebrae: the last insertion is fleshy and strong; the 

 four anterior of these insertions are concealed by the upper and 

 outer fleshy portions of the sacro-lumbalis, which divides into five 

 elongated fleshy bundles, inserted successively into the diapo- 

 physes of the first three dorsal and last two cervical vertebra?. 



Muscles of a Hawk. 



1 XXIV. vol. iii. p. 280, pis. 32 and 33. 



