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. 148, 7; Fig. 141, y; Fig. 150, 
z) is a fusiform or ovoid elevation of thé floor of the lateral ven- 
tricle. One of its narrow ends lies about opposite the middle 
Fic. 152. CAUDAL SURFACE oF Fic. 153. — CAuDAL SURFACE OF 
TRANSVERSE SECTION OF THE TRANSVERSE SECTION OF THE BRAIN 
BRAIN THROUGH THE PINEAL THROUGH THE CRANIAL PAIR OF 
Bopy AND THALAMI. CORPORA :‘QUADRIGEMINA. 
Fig, 152.—a, corpus callosum; 4, fornix; ¢, inferior horn of lateral ventricles; 
d, hippocampus; ¢, thalamus; /, third ventricle; g, pineal body; 4, space between 
the floor of the hemisphere (hippocampus) and roof of the ’tween-brain (thalamus). 
Fig. 153.—a, cranial corpora quadrigemina; 4, hippocampus; ¢, part of inferior 
horn of lateral ventricle; ¢, aqueductus cerebri (aqueduct of Sylvius); ¢, space 
between the outer surface of the midbrain and the lower surface of the hemisphere; 
J, cross-section of midbrain; g, pedunculi cerebri. 
of the thalamus (Fig. 141, 7) 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, ¢). Internally the corpus striatum is 
made up of several layers of different texture (Fig. 150, 2), 
whence its name. 
The choroid plexus of the lateral ventricles (lamina 
chorioidea epithelialis) (Fig. 148, ¢).—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, 2). 
Along this line (Fig. 141,1) 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. Inan early stage, before 
