356 



NERVOUS SYSTEM. 



surface of the tuber cinereum. It bears at its ventral end the 

 hypophysis (pituitary body) (Fig. 138,^), a vascular non-ner- 

 vous body of unknown function. The hypophysis is lodged in 

 the sella turcica of the sphenoid bone. 



At its caudal border the tuber cinereum bears two white 

 elevations, the mammillary bodies (corpora mammillaria) 

 (Fig. 142, g). 



The third ventricle (Fig. 143, //; Fig. 141, v) is a very 

 narrow slit-like space, of considerable extent dorsoventrally, 

 but less than a millimeter in width ; it lies between the medial 



z,Y 



FIG. 143. LONGITUDINAL MEDIAN SECTION OF BRAIN. 



J, olfactory bulb; //, cerebrum; ///, section of cerebellum, showing "arbor 

 vitse " ; IV, medulla oblongata. a, tractus olfactorius; 6, substantia perforata an- 

 terior; c, anterior commissure; d, lamina terminalis; e. optic chiasma; _/", massa in- 

 termedia of thalamus; g 1 '. infundibulum; g, hypophysis; //. third ventricle; z, mammil- 

 lary body ; /, aqueductus cerebri (or aqueduct of Sylvius) ; k, pons ; /. velum medul- 

 lare anterius; m, fourth ventricle; , velum medullare posterius; o, continuation of 

 canal of spinal cord; /, corpus callosum (body); q, genu of corpu callosum; r, ros- 

 trum; s, splenium; t, septum pellucidum; , fornix; v, pillars of fornix; w, choroid 

 plexus of third ventricle; x. stria medullaris; y, corpus pineale; z, cranial corpus 

 quadrigeminum ; z', posterior qommissure. I, sulcus falcialis; 2, sulcus cruciatus; 

 3, sulcus splenialis; 4, sulcus marginalis; 5. sulcus supracallosalis (or callosalis). 



ends of the thalami (Fig. 141), and extends ventrad into the 

 tuber cinereum, and thence into the infundibulum (Fig. 143, 

 g'}. Dorsad it extends into the corpus pineale (Fig. 143, j). 

 The third ventricle communicates caudally near its dorsal 

 border with the aqueductus cerebri (/); craniolaterally with 

 the lateral ventricles, through the interventricular foramen 



