INTERNAL PARTS. 



516 



convolution). The fascia dentata can be traced up to the pad or bour- 

 relet : its upper part is free of dentations, and is sometimes named 

 fasciola cinerea. The dentations correspond with blood-vessels passing- 

 to and from the choroid plexus. 



Fig. 382. 



Fig. 382. — View of the Upper Surface op the Velum Interpositum, Choroid Plexus, 

 AND Corpora Striata (from Sappey after Vicq-d'Azji-). g 



1, fore part of the tela choroidea or velum interpositum ; 2, choroid plexus ; 3, left 

 Teio of Galen partly covered by the right ; 4, small veins from the front of the corpus 

 callosum and the septum lucidum ; 5, veins from the corpus striatum ; 6, convoluted 

 marginal vein of the choroid plexus ; 7, vein rising from the thalamus opticus and corpus 

 striatum ; 8, vein proceeding from the inferior cornu and hippocampus major ; 9, one 

 from the posterior cornu ; 10, anterior pillars of the fornix divided in front of the fora- 

 men of Monro ; 11, fornix divided near its fore part and turned backwards ; 12, lyra ; 13, 

 posterior pillar of fornix united with, 14, the corpus callosum behind, and covered by 

 the choroid plexus as it descends into the inferior cornu. 



The velum interpositum or tela choroidea (fig. 382), the mem- 

 brane which connects the choroid plexuses of the two sides together, is 

 a prolongation of the pia mater through the transverse fissure. It 

 corresponds in extent with the fornix, which rests upon its upper sur- 

 face ; and its more highly vascular free borders, projecting into the 

 lateral ventricles, form the choroid plexuses. 



The choroid plexuses (fig. 382, 2) appear like two knotted fringes 

 reaching from the foramen of Monro, where they meet together beneath 



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