26 MORPHOLOGY OF THE VERTEBRATA. 



URETERS, 



The duct of the kidney, is continued along the anterior surface of, 

 the kidney, receiving branches of the urinary tubules as it passes 

 along. Below the kidney the ureters pass behind the rectum, 

 becoming blended with its coats : they ultimately terminate upon 

 valvular elevations in the cloaca. 



The supra-renal capsules or adrenals are of- a bright yellow 

 colour, and are placed on the inner side of the superior extremities 

 of the kidneys. They are in contact with the testes in the male, 

 and the left one adheres to the ovary in the female. They have 

 been found to shew an enlargement corresponding to the increased 

 development of the sexual organs. Their function is unknown. 



TESTES, 



Two in number, of an oval form, are placed near the upper end of 

 the kidneys, the left being usually larger than the right. They 

 are enclosed within a strong tunica albuginea, and are fastened by 

 a fold of peritoneum to the spine. They acquire an immense size 

 at the breeding season. The vas deferens, the duct of the testes, 

 passes down by the side of the ureters,, and opens on a papilla in 

 the cloaca anterior to the opening of the ureter. The base of each 

 papilla is surrounded by a plexus of arteries and veins, and 

 serves as an erectile organ during coitus. 



OVARY, 



Only one, on the left side. The fallopian is long and tortuous, and 

 the ovum or egg, as it passes along it, receives the albuminous 

 investment — the so-called white of egg, which would serve for the 

 nutrition of the embryo had impregnation taken place. At its 

 lower end the fallopian tube is dilated, and it is in this situation 

 that the egg receives the calcareous shell. Lastly, the fallopian 

 tube opens into the cloaca, where the egg is received. 



RESPIRATORY ORGANS. 



THE LUNGS 



Are spongy in texture, and of a bright crimson colour. They are 

 situated in the thoracico-abdominal cavity, and are firmly attached 

 to the, ribs and. their interspaces on either side, of the vertebral 

 column, each lung being, moulded to the superjacent vertebrae and 

 ribs. They communicate with the large air sacs which extend 

 into the abdomen. 



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