Dufiorphisj}! and Regeneration in Metruiium. 229 



polyps derived from monoglyphic parents had the directives 

 developed in new tissue in all except one of twenty-six cases, in 

 which the limits of old and new tissue could be recognized. In 

 that one case the directives clearly were attached to the old or 



Fig. 



Fig. 2. 



r* Fig. i. Cross section of a diglyphic polyp produced by a fragment cut from the foot-disc of a 

 diglyphic parent in such a way as to include a pair of directive mesenteries. The parental directives 

 lie in the upper half of the figure, the regenerated directives in the lower half. The ectoderm is 

 stippled in the regenerated portion of the body-wall. (From a camera lucida drawing, histological 

 details being omitted.) 



Fig. 2. Cross section of a monoglyphic polyp produced by a fragment cut from the foot-disc of a 

 diglyphic polyp so as not to include directive mesenteries. The regenerated portion of the body-wall is 

 indicated, as in Fig. i, by stippling of the ectoderm. The single short pair of directive mesenteries is 

 attached to this portion of the body-wall. (From a camera lucida drawing, histological details being 

 omitted.) 



parental part of the body-wall. It would seem, accordingly, 

 that in this exceptional case no directives had been produced in 

 the new tissue. Had this taken place the polyp would have been 

 diglyphic, with the directives arranged exactly as in the twelve 



