108 STRUCTURE AND CLASSIFICATION OF BIRDS 



Depressor Coccyyis. This springs from the transverse 

 process of the last sacral vertebra, and from the adjacent 

 surface of the ilio-sacral ligament. It is inserted on to the 

 transverse processes of the last three or four caudal vertebrae. 



Abdominal Muscles 



ObliquiLs Abdominis Externns. The muscle arises from 

 the ribs and from their uncinate processes. It ends by an 

 aponeurosis upon the pubis. 



Obliquus Abdominis Interims. Lies between the last 

 muscle and the next. It passes from the pubis, extending 

 on to ilium to the last true rib. A separate slip of this is 

 described as the quadratus lumborum, running from the last 

 false rib to the crest of the ilium. 



Transversus Abdominis. This is the deepest of the ab- 

 dominal muscles. It springs from the pubis and preace- 

 tabular ilium, and its aponeurosis ends in that of its fellow 

 in the linea alba. 



Eectus Abdominis. Springs from last sternal rib and 

 from sternum, and is attached to pubis. 



Transverso-analis. This passes across the abdomen in 

 front of the cloacal aperture, and meets its fellow. It arises 

 either from the pelvis or from the transverse processes of 

 certain caudal vertebrae. 



Hyoidean Muscles 



Our knowledge of the muscles of the hyoidean apparatus 

 and the neighbourhood is chiefly due to GiEBEL, 1 GADow. 2 

 and MITCHELL. 3 I mainly follow the latter in his account 

 :)f these muscles in Opisthocomus and in Palamedea. 



c 



' Die Zunge cler Vogel,' &c., Zeitschr. f. d. ges. Katiirwiss. xi. 1858, p. 19. 

 - BRONN'S Thierreich, ' Aves.' 



' A Contribution to the Anatomy of the Hoatzin (Opisthocomus cristatus),' 

 P. Z. ,S'. 1816, p. 618 ; BEDUAHD and MITCHELL, ' On the Anatomy of Palamedea 

 cornuta; P. Z. ,S'. 1894, p. 536. See also G. L. DUVKHNOY, ' Memoire sur 

 quelques Particularites cles Organes cle la Deglutition de la Classe des Oiseaux,' 

 Ac., M6m. Soc. Hist. Nat. Strasbourg, ii. 1835 ; J. KACZANDER, ' Beitriige zur 

 Entwicklungsgeschichte cler Kaumuskulatur,' Mtli. Embr. last. Wien, 1883. 



