THE LATERAL VENTRICLE. 115 



Floor (from before, backward and inward) 



Caudate nucleus of the corpus striatum, 



Stria terminalis (taenia semicircularis), 



Thalamus (covered by epithelium), 



Lamina chorioidea epithelialis and chorioid plexus, 



Fornix. 



Medial wall Septum pellucidum. 

 External wall Internal capsule. 



The corpus callosum forms a complete roof for the central part 

 of the lateral ventricle. The roof inclines upward and outward 

 from the septum pellucidum, the inner wall of the ventricle, to 



JL Fig. 33. Diagram of internal capsule in colors. (Original.) 



RED, motor; BLUE, common sensory; PURPLE, special sensory. 



the superior lamina of the internal capsule, which forms its outer 

 wall. The floor of the central part of the ventricle is formed by 

 the five parts, as named above, which will now be considered 

 in the order given. 



Corpus Striatum (Figs. 30, 31, 32 and 40). The striated body 

 is the basal ganglion of the hemisphere. It is an ovoid mass of 

 gray matter imbedded, for the most part, hi the cerebral medulla ; 

 but it is continuous below with the anterior perforated substance, 

 and extends above to the lateral ventricle. It measures two 

 and a half inches from before backward, an inch and a quarter 



