SAXGUIFEROUS SYSTEM. 499 



coccyx. The descending aorta in passing backwards, sends 

 out considerable cesophageal and bronchial arteries, a variable 

 number of intercostal trunks, and numerous smaller dorsal 

 and lumbar branches to the parts around the spine. The 

 cceiiac artery is here a considerable trunk, which is devoted 

 chiefly to the alimentary canal and the gastric cavities, the 

 branches being small which proceed to the chylopoietic 

 glands. This great cceiiac trunk sends a branch forwards to 

 the oesophagus, another the gastric to the ventriculus succen- 

 turiatus and the gizzard, and much smaller branches to the 

 spleen, the liver, and the pancras, and where the coeca-coli 

 are of considerable size they also receive a separate branch 

 from the same trunk. The chief continuation of the coeliac 

 artery, after giving off small branches to the oesophagus the 

 spleen and the liver, generally divides into a right and a left 

 gastric artery which spread on the corresponding sides of 

 the gizzard, the right sending out a branch to the duodenum 

 and pancreas, and another to the mtestinum ilium and cosca- 

 coli, and the left giving branches chiefly to the ventriculus 

 succenturiatus and the left lobe of the liver. 



From the high origin of the external iliac or crurel arteries in 

 birds, only one mesenteric, the superior mesenteric artery, arises 

 from the trunk of the aorta, above the commencement of these 

 vessels, as in the class of reptiles. This vessel arises a little below 

 the coeliac, from the fore part of the aorta, and spreads its 

 ramifications over most parts of the mesentery, the intestinal 

 canal and the cceca-eoli, anastomosing anteriorly with 

 branches of the gastric arteries, and posteriorly, on the 

 rectum, with branches of the small posterior mesenteric 

 which arises from the median sacral artery. Below the 

 superior mesenteric, the common trunk of the right and 

 left genital or spermatic arteries arises from the fore part of 

 the aorta, and each of these arteries sends a branch to the 

 upper large lobe of the kidney, and another to the testicle 

 or to the ovary and oviduct, of its respective side, these 

 genital branches having a tortuous course, and being subject 

 to periodical enlargements with the genital organs, as in 

 other animals. The right and left profuncUefemoris or deep- 

 seated femoral arteries have separate origins from the 

 sides of the aorta in birds, and distribute their branches to 

 the muscular parts of the abdomen and femur as far as the 



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