^ 



LESSON 85.] NERVOUS SYSTEM IN BIRDS. 275 



the inferior surface of the hemispheres, and taper forwards to the 

 olfactory nerves. The optic lobes, from whence the optic nerves 

 arise, are shown at c, the nerves of motion of the eye, or motor oculi 

 (</), are also well developed. 



1238. The large cerebellum (ra), with its lateral lobes (I), is also 

 well seen; the medulla oblongata (b) terminates in the spinal 

 chord (a). 



1239. An illustration is offered of the brain of the Buzzard 



FIG. 391. 



Brain of the Stork. 



(Fig. 392) ; the olfactory ganglia are entirely concealed, in this view, 

 by the great size of the cerebral hemispheres (a). The optic gan- 

 glia (b) are seen of large size ; the cerebellum (c), and the pineal 

 gland (d))j with (e) the spinal chord, completes the view. 



1240. The sensitive spinal nerves of birds have the ganglia larger, 

 and approximate more nearly to their origin than in reptiles ; and 

 from the retraction and high termination of the spinal chord, as well 

 as the comparative magnitude of the legs in this class, the posterior 

 ganglionic enlargement is remarkable for its size, and at this place 

 the motor and sensitive roots pass out through separate foramina 

 (holes) of the numerous sacral (sacrum, the back) vertebra. 



The twelve pairs of cranial nerves are distinct, as in reptiles and 

 mammalia. The smallness of the facial nerve corresponds with the 

 immobility and insensibility of the superficial parts of the face, and 

 the magnitude of the acoustic nerve, with the great development of 



