The tela choroidea of the prosencephalon in cat is vascularized by an anterior choroidal artery arising from the carotid system and by a posterior choroidal artery arising from the vertebral basilar system. The first essentially supplies the tela and the choroid plexus of the lateral ventricle. The second above all supplies the tela choroidea of the third ventricle. Both, the anterior and posterior choroidal arteries anastomose with their terminal branches. The choroidal branches which arise from these arteries nourish the capillary networks of the tela. These vessels drain into venules and veins which are tributary of the venous circle of the base and of the internal cerebral veins.