DEVELOPMENT OF THE CHOROID PLEXUS 



93 



The tela chorioidea diencephali is very broad and very thin 

 (fig. 11, Led.). It does not exhibit any folding except at the 

 extreme anterior end. Toward the posterior end of the tela, a 

 narrow strip of the alar plate is curved lateralward, resembling 

 the rhomboidal lip of the rhombencephalon, and which we may 

 term the thalamic lip (fig. 9, /./.). 



Fig. 7 Sec-tion through the roof plate of (elcn(ei)li:il()ii moiliiiiii i>f the "JN in 

 embryo, H 91. X 50. Slide, 29, Sect. 372. 



Fig. 8 Section through the roof plate of te]cn(ei)h:il()n inediiiin in the 32 in 

 cinbrvo, H 41 . X 50. Slide 32. Sect. 2. 



The thalamic lip carries with it lateralward the taenia thahiini 

 (fig. 9, t.t.) and the roof plate. Toward the anterior end of the 

 tela, the thalamic lip bends laterally more and more until its 

 pial surface comes into contact with the pial surface of the tha- 

 lamic wall (fig. 11, t.l). The ependymal surface of the roof plate 

 is hereby brought into contact with the ependymal surface of 

 the thalamic lip (fig. 11). At the apex of the angle between the 

 thalamic lip and the thalamic wall lies the stria medullaris (fig. 

 11, S.771.). The entire tela when viewed from above is wedge- 



