526 TEXT-BOOK OF PHYSIOLOGY. 



Island of Reil. The general appearance and relation of these nuclei, 

 are shown in Figs. 243 and 244. A horizontal section of the lenticular 

 nucleus shows that it is divided by two lamina of white matter into three 

 portions. The two inner, from their pale yellow color, form the globus 

 pallidus, the outer, somewhat darker in color, is termed the putamen. 

 External to the lenticular nucleus is a thin stratum of gray matter, 

 arranged more or less vertically, and placed between the outer surface 

 of the lenticular nucleus and the cortex of the Island of Reil, and 

 known as the daustrum. 



FIG. 242. CORPORA STRIATA, OPTIC THALAMI, CORPORA QUADRIGEMINA, CEREBELLUM AND 

 ASSOCIATED STRUCTURES, i, Corpora quadrigemina; 2, valve of Vieussens; 3, pre-peduncle 

 4, upper part of medi-peduncle; 5, upper part of crus; 6, lateral fillet; 7, band of Reil; 8, post- 

 brachium; 9, frenulum; 10, gray matter of valve of Vieussens; n, medi-commissure; 12, pre-com- 

 missure; 13, 14, center of cerebellum; 15, post-commissure; 16, peduncles of the pineal gland; 17 

 pineal gland; 18, 19, posterior and anterior tubercles of the thalamus; 20, teniasemicircularis; 21, 

 vessels of the corpus striatum; 22, fornicolumn; 23, corpus striatum; 24, septum lucidum. 

 (Sappey.) 



The Optic Thalamus is an oblong mass of gray matter situated between 

 the sensor, afferent pathway and the cortex of the cerebrum. The anterior 

 and posterior extremities of each thalamus present enlargements known 

 respectively as the anterior tubercle and the posterior tubercle or pulvinar 

 The mesial surface of the thalamus forms the lateral wall of the third ventri 

 cle and is covered by epithelium resting on a thin layer of ependyma. 



A transection of the thalamus shows that it is not only covered externally 

 but penetrated by white matter, which subdivides its contained gray cells 



