ANATO:\[Y OF THE FOWL 



37 



It connects the 



in a thread-like 



fourth ventricle is located under the cerebellum. Lateral 

 pedicles attach it to the lower structures. The medulla ob- 

 longata is broader than the spinal cord, 

 spinal cord with the brain. 



The spinal cord terminates posteriorly 

 termination without forming^ a 

 eauda equina as in mammals. There 

 are cervical and lum])ar segments 

 from which are given off nerves for 

 the wings and the hind extremities. 

 The dorsal segment is marked by 

 an enlargement. The central canal 

 as well as the mode of entrance and 

 exit of the fibers is the same as in 

 mammals. 



The number of nerves that are 

 given off from the spinal cord de- 

 pends upon the number of vertebral 

 segments. The spinal nerves are 

 given off in pairs ; each nerve orig- 

 inates from one dorsal and one 

 ventral root, as in mammals ; one 

 nerve for each side of the body. 

 The spinal ganglion is located on 

 the dorsal root. Each spinal nerve 

 divides into a small dorsal nerve 

 supplying the muscles and other 

 structures in the region above the 

 level of the spinal column and a 

 larger ventral branch supplying the 

 body walls below the level. The 

 spinal nerves have been placed in 

 four groups, as follows; cervical 

 (neck), dorsal (back), lumbar 

 floin), and caudal (tail) nerves. 

 The wings receive their nerve sup- 

 ply from the brachial plexus. The 

 brachial plexus is made up of the 

 last two or three cervical nerves 

 and the first one or two dorsal 

 nerves. The structures in the pel- 

 vic region are supplied from 

 branches of the ventral branches 

 of the lumbar nerves. The nerves 



of the shoulder and pelvis are essentially the same as in mam 

 mals. The nerves of the skin and tail are small. 



Fig. 9. Brain and Eyeball of thk 

 FowLj Slightly Enlarged. 



A — 1, the olfactory nerves; 2, 

 the optic nerve; 3, pituitary 

 gland, slightly dislodged poste- 

 riorly; 4, optic lobes; 5, medulla 

 oblongata; 6, optic chiasm; 7, 

 right cerebrum; 8, eyeball; 9, 

 sclera; 10, cornea. 



B — 1, optic nerve; 2, its sheath. 



C — 4, optic lobes; 5, medulla 

 oblongata; 7a, right and 7b, left, 

 cerebral hemispheres; 8, cerebel- 

 lum; 9, fissure longitudinalis; 10, 

 fissure transversalis. 



