PLATE D. 



Continuation of embryology of Phalangella flabellata. 

 Explanation of lettering. 

 (Jy Ectocyst. r, Rectum. 



6, Endocyst. v, Terminal disc of tentacular tube. 



n, Tentacles. w. Stomach. 



o, Fatty globules. z, " Zone anhiste." 



Fig. 18. A more advanced stage ; a little beyond the center is a 

 discoidal plate, formed by the tubular uprising of the 

 surface. 

 Fig. 19. The uprising of the surface under the disc v has formed a • 

 long tube (tentacular tube) ; the disc has changed from a 1 

 horizontal position to a vertical on account of the unequal 

 increase of the two faces of the tube, and has the beginning 

 of an^ opening (opening of the cell). The rudimentary 

 polyp begins to acquire a definite structure. 

 Fig. 20. The ectocyst is greatly thickened, and has formed on the 

 tentacular tube. The fatty globules are condensed in two 

 masses o. 

 Fig. 21. The polyp has reached the complete state 



anhiste " has disappeared. 

 Fig. 22. The primitive cell and tentacular tube more developed 

 Fig. 23. A profile view of a cell; 

 Fig. 24. Showing the manner of increase of the cells. 



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