THE STRUCTURE OF THE VERTEBRATES 



337 



ducing movements of the stomach, do not rise into the 

 field of consciousness. Thus we have : (a) unconscious 



-md. 



After Wiedersheim 



FIG. 124. Brain of a European rabbit. A, dorsal view; B, ventral view; b.o., 

 olfactory lobe ; cb', median, and cb", lateral lobe of cerebellum ; cr, crura cerebri ; 

 ep, epiphysis ; f.p., longitudinal fissure ; f.b., cerebral hemisphere ; hp., hypophysis or 

 pituitary body; m.b., mid brain; md., medulla oblongata; pv., pons Varolii; i xii, 

 cranial nerves. 



activities ; (&) conscious activities not or little con- 

 trolled by the brain ; (c) conscious activities under full 

 mental control. The proportions of these can be 

 roughly estimated from a study of the nervous system. 



The blood system is not peculiar to vertebrates. The blood 

 Blood is a fluid containing free cells or corpuscles, which 

 are of two sorts. The more numerous are rigid and 

 disklike, and contain hemoglobin, which gives the red 

 color to the blood. These red corpuscles (which are 

 really pale yellow when seen singly) are usually ellipti- 

 cal, but in mammals (except the camel family) they are 

 circular ; in mammals, also, they are without the nuclei 



