Davekpobt. — Budiiiug iu Br^ozoa. 



PLATE XII. 



ABBREVIATIONS. 



ec'drm. Ectoderm. ms'drm. Mesoderm. 



ex. Outer layer of bud. ote. Ooecium. 



i. Inner layer of bud. sto. Stolon. 



lu. am. Lumen of the bud. 



Fig. 100. Longitudinal section of a larva of Plumatella polymorplia, in which the 

 two layers are established; tiie pole of ingression is directed upward, 

 on the plate. 



Fig. 101. Section of upper part of zooecium of Cristatella miicedo, with its contained 

 larva. Showing the formation of the stolon at the pole of Ingres 

 sion and the attachment of this pole to the placenta-like neck of the 

 oceciura (*). X 390. 



Fig. 102. Section through an ooecium of Cristatella, with its contained larva. One 

 polypide is already established, and a second is arising. Tiie two 

 are the only buds in tlie larva. On the left of the older bud the 

 stolon is seen to be intruding itself between the ectoderm and meso- 

 derm of the larva. X 390. 



Fig. 103. Section through the two oldest polypides of the Cristatella larva, to- 

 gether with the stolon. This larva contains one other less developed 

 bud at one side of these two. X 390. 



Fig. 104. Plumatella poli/ir.orpha. Stage of first bud later than that shown in 

 Figure 96, exhibiting pore of invagination closed by overgrowth of 

 ectoderm. X 390. 



