Journ. Morph. xii. 1896, p. 149.
See Pizon, Ann. des Sci. Nat. 7e sér. Zool. xiv. 1892.
"Oozooid" and "blastozooid" have not always been used in the same sense. It is best to regard as oozooid the first member of a new colony derived from an embryo formed by the fertilisation of an ovum, and to call the remaining ascidiozooids produced by gemmation the blastozooids.
According to Kowalevsky. Salensky, however, considers that the atrial aperture closes, and that a new surface depression appears later.
See Barrois, Journ. d'Anat. et Physiol. 1885.