part_of adult ovary adult ovary tunica propria Fig. 16-24, Fig. 16-27, in Biology of Ticks ISBN:0-19-505910-7. TADS:0000404 TADS:0000404 The tunica propria is the amorphous lamellate sheath comprised of multiple layers of fibrillar material, collectively about 1micron thick. The tunica propria extends (folds) around each of the developing oocytes and forms an outer covering as they enlarge. The tunica propria is believed to be permeable to vitellogenin and other hemolymph proteins. default_namespace acellular anatomical structure