AORTIC ARCHES OF BIRDS — GLENNY 



549 



The right systemic arch alone remains as the functional vessel carry- 

 ing blood from the aortic root to the functional radix aortae. Biswas 

 (1946) has reported the occurrence of both a left and right systemic 

 arch in a specimen of Ploceus pkilippinus philippinus, along with a 

 patent left radix aortae which was occluded at the posterior end. 

 A left ligamentum botalli was present in this specimen. 



J 



'^ fW 



Y 



Figure 112. — Arrangements of the dorsal carotid arteries and the associated cervical and 

 thoracic arteries in Aves Unicarotidinae (ventral views). Types (for code see pp. 546, 

 548-549): a, B-2-d; b, B-1; c, B-2-s; d, B-3a-d; <r, Bh5-s; f, B-3a-s; g, B-3b-d; h, B-4-s; 

 t, B-4-d. 



