THE CENTRAL NERVOUS SYSTEM. 



367 



Along the craniolateral edge of the hippocampus is a broad, 

 clearly marked fibre-tract, the fimbria ; this runs parallel to 

 the choroid plexus of the lateral ventricle and beneath it, and 

 is continuous at its medial end with the fornix. 



The corpus striatum (Fig. H8,/; Fig. 141,7; Fig. 150, 

 i ) is a fusiform or ovoid elevation of the floor of the lateral ven- 

 tricle. One of its narrow ends lies about opposite the middle 



^ ?\ ^r^/ a A 



.a 



FIG. 152. CAUDAL SURFACE OF 

 TRANSVERSE SECTION OF THE 

 BRAIN THROUGH THE PINEAL 

 BODY AND THALAMI. 



FIG. 153. CAUDAL SURFACE OF 

 TRANSVERSE SECTION OF THE BRAIN 

 THROUGH THE CRANIAL PAIR OF 

 CORPORA QUADRIGEMINA. 



Fig. 152. a, corpus callosum; b, fornix; f, inferior horn of lateral ventricles; 

 d, hippocampus; e, thalamus; f, third ventricle; g, pineal body; h, space between 

 the floor of the hemisphere (hippocampus) and roof of the 'tween-brain (thalamus). 



Fig. 153. rt, cranial corpora quadrigemina; b, hippocampus; <", part of inferior 

 horn of lateral ventricle; d, aqueductus cerebri (aqueduct of Sylvius); e, space 

 between the outer surface of the midbrain and the lower surface of the hemisphere; 

 f, cross-section of midbrain ; g, pedunculi cerebri. 



of the thalamus (Fig. 141, /) and it extends thence obliquely 

 mediad nearly parallel with the thalamus. In the groove 

 between it and the thalamus is the choroid plexus of the lateral 

 ventricles (Fig. 148, e). Internally the corpus striatum is 

 made up of several layers of different texture (Fig. 150, z), 

 whence its name. 



The choroid plexus of the lateral ventricles (lamina 

 chorioidea epithelialis) (Fig. 148, e). The line of junction of 

 the roof of the third ventricle (i.e., the choroid plexus of the 

 third ventricle) and the cerebral hemispheres is along the 

 lateral (or cranial) border of the thalamus (Fig. 141, /). 

 Along this line (Fig. 141, i) the brain-wall remains very thin 

 and becomes closely associated with the pia mater, so that on 

 the removal of the pia there is left the ' ' transverse fissure ' ' 

 which leads into the lateral ventricle. In an early stage, before 

 the cerebrum has grown far caudad, the fissure is exposed in 



