20 THE farmer's VETERINARIAN 



from the base of the skull to the pelvis, furnished 

 with ganglionic enlargements and connected with 

 the spinal nerves by small fibers. 



The Respiratory Organs. — These include the 

 nose, larynx, trachea or windpipe, and lungs. The 

 trachea forks into bronchi and bronchioles of 

 smaller and smaller size, ending in the alveoli 

 or blind sacs of the lungs. In fowls there are 

 numerous extensions of the respiratory system 

 known as air sacs, and located in the body 

 cavity and also in the hollow bones. The air sacs 

 communicate with the lungs, but not with one an- 

 other. 



The Urinary Organs. — These consist of kidneys 

 connecting by means of ureters with a bladder from 

 which the urethra conducts the urine to the out- 

 side. In the male the urethra passes through the 

 penis and in the female it ends just above the 

 opening of the vagina. The kidneys are usually 

 inclosed in a capsule of fat. The right kidney of 

 the horse is heart-shaped, the left bean-shaped. 

 Each kidney of the ox shows 15 to 20 lobes, and is 

 oval in form. The kidneys of sheep, goats, and 

 swine are bean-shaped and without lobes. 



The Reproductive Apparatus. — This consists of 

 ovaries, oviducts, uterus or womb, and vagina in 

 the female; the testes, spermatic cords, seminal 

 vesicle and penis, together with various connecting 

 glands, especially prostate gland and Cowper's 

 gland, in the male. In fowls there is no urinary 

 bladder, but the ureters open into the cloaca or 

 posterior part of the rectum. The vagina and 

 uterus are also wanting in fowls, the oviducts open- 

 ing directly into the rectum. The male copulating 

 organ is absent except in ducks, geese, swan, and 

 the ostrich. 



