Morphology of the Madreporaria. 



103 



in Madrepora that a satisfactory solution of iheir presence 

 was readied. Full consideration of them will be deferred 

 until later. In the meantime it will be noticed that eight 

 mesenterial insertions — four primary and four new — are 

 associated with each stomodaeum, which is the number charac- 

 teristic of an ordinary adult polyp ; also that four incomplete 

 mesenteries belong to each polypal half. Thus, regarding 

 each of the mesentery-like strands as representing two mesen- 

 teries, the full complement of twelve mesenteries is associated 

 with each stomod?eum, as if the latter were separate polyps. 



ir B 



Transverse section through the stouiodseal region of another enlarged 

 polyp, with the dorsal and lateral areas free. Only a single mesen- 

 terial strand connects the stomodasal tubes. New mesenteries, A-D, 

 have been added within the ventral entocojle, and one pair, E, E, 

 within the dorsal eutocoile. 



Fig. 5 displays a further stage in the mesenterial develop- 

 ment. There are now seven complete mesenteries extending 

 from each stomodteum to the body-wall, and only a single 

 connecting strand. Evidently the two additional complete 

 mesenteries {E, E) represent the dorsal member of the two 

 connecting mesenteries in the previous tigure. They now 

 form a new bilateral pair situated at the upper aspect of the 

 polyp — that iSj within the entocoele of the dorsal directives 

 (/K, IV)^ and the musculature is so disposed that the mesen- 

 tery to the left constitutes a pair of directives with the primary 

 directive mesentery on that side, and likewise with the two 



