Budding in Perophora

int where a bud is beginning to form. The ectoderm on one side is thickened, and the double-walled partition is much thickened and dilated. X 500. Fig. 8. Transverse section through a very young bud-rudiment and stolon, at about the stage of Fig. 1, PI. XXIX. The walls of the partition are coming together to close off the inner vesicle, in.v. Blood cells are found lying against the outer surface of the latter. X 500. Fig. 9. Transverse section through posterior end of a bud-rudiment at about the stage of Fig. 3, PI. XXIX, showing thick wall of inner vesicle on right side, r.w.in.v., and beginning of pericardial rudiment, pc.r. X 500. Fig. 10. Transverse section through posterior end of a young bud, showing an early stage in the displacement or shifting of the inner vesicle. The wall of the latter is being bent in at the point indicated by the line a. X 200. Fig. 11. Transverse section through posterior end of bud slightly older than last, showing further progress of the displacement of the vesicle. The pericardial rudiment, pc.r., is at a much lower level than in the last figure, and the wall of inner vesicle is being bent in further at a ; this is the fold which will form the left peribranchial sac,//./.j. X 200. FlG. 12. Transverse section through the middle region of same bud as the one shown in Fig. II. The section lies in front of the connection with the sto- lonic partition, and shows the beginning of the fold which will form the right peri...