52 



STRUCTURE AND CLASSIFICATION OF BIRDS 



The arterial system of birds 1 is chiefly remarkable for the 

 large number of the different arrangements of the carotids. 



FIG. 32. NORMAL AVIAN CAROTIDS. 



i:c, J.c, carotids ; r.s, l.s, subclaviaus ; r.i, l.i, 

 right and left innominate ; a, aorta ; ?i, 

 its origin. (This aiid five following figs, 

 after UAIIROD.) 



FIG. 34. CAROTIDS OF FLAMINGO. 

 LETTERING AS IN FIG. 32. 



r.s 



l.s 



FIG. 33. CAROTIDS OF BITTERN. 

 LETTERING AS IN FIG. 32. 



r.s 



FIG. 35. CAROTIDS OF Cacatua. 

 LETTERING AS IN FIG. 32. 



Many writers, especially NITZSCH, among the earlier anato- 

 mists, have drawn attention to some of these variations. 



1 L. A. NEUGEBATJER, ' Systema Venosum Avium,' Nov. Act. Acad. Nat. Cur. 

 xxi. 1845, p. 517 ; EATHKE, ' Uber die Caroticlen . . . cler Vogel,' Arch. f. Anat. u. 

 Phys. 1850, p. 184, and ' Bemerk. liber die Entstehung, &c., der gemeinsch. 

 Carotis,' ibid. 1858, p. 315 ; GARROD, ' On the Carotid Arteries of Birds,' P. Z. S. 

 1873, p. 457 ; C. H. WADE, ' Notes on the Venous System of Birds,' J. Linn 

 Soc. xii. 1876, p. 531 ; F. HOCHSTETTER, ' Beitriige zur Entwicklungsgeschichte 

 des Venensystems,' &c., Morph. J.B. xiii. 1888, p. 575, and ' tiber den 

 Ursprung der Subclavia d. Vogel,' ibid. xvi. 1890, p. 484. 



