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arteries, and is then continued as the dorsal aorta. Each 

 innominate divides into a common carotid and a subclavian, 

 which divides into brachial and pectoral arteries. Arching 

 to the right side, the dorsal aorta then passes mid-dorsally 

 backwards ; its principal branches are the coeliac (to 

 stomach), the anterior mesenteric (to intestine), renals, 

 femorals, sciatics, iliacs, and a posterior mesenteric (to 

 rectum) ; and it ends as the caudal artery. 



* Since the femorals give off small veins to the kidneys, there is a 

 trace of a renal portal system. 



Write a Short Account of the Renal and Reproductive Organs 

 of the female Pigeon. 



The three-lobed kidneys are embedded in the pelvis; 

 at their front ends are the small yellow adrenal bodies. 

 The narrow ureters, each arising from the front lobe, pass 

 backward to the cloaca. There is only one, the left ovary ; 

 it is anterior to the left kidney. The left oviduct is a 

 convoluted tube ; its anterior opening (coelomic funnel) 

 is close to the ovary, and posteriorly it opens into the 

 cloaca. When a follicle bursts, the egg is discharged into 

 the body cavity, and it enters the oviduct. The middle 

 portion of the oviduct forms the white or albumen around 

 the egg, the hind portion secretes the shell ; the terminal 

 part, the muscular vagina, ejects the egg. 



Development of Birds. 



Write a General Account of the Development of the Chicle. 



The spherical yellow ovum, within a vitelline membrane, 

 consists of a large amount of yolk with a small germinal 

 disc (containing the nucleus) at the surface ; and it is 

 surrounded by a mass of viscid albumen, which is denser 

 close to the ovum and there twirled out into two twisted 

 ends, the chalazae. The outer limy shell has two lining 

 membranes ; at its broad end these are separated to form 

 an air-chamber. 



Segmentation is meroblastic and restricted to the disc, 

 which becomes the blastoderm, with an upper layer of cells 

 (ectoderm) and larger lower layer cells, the lowest being 

 incompletely separated from underlying yolk-nuclei. The 

 spaces between the lower layer cells represent the segmen- 

 tation cavity, soon obliterated. The lowest lower-layer 

 cells become flattened and joined together to form the 

 (secondary) endoderm or hypoblast. The blastoderm spreads 



