(65) 



Ventral Mo sent e ry :_-_ The veiitral uicaeulerj of the Actino- 

 trocna, 1 believe, becomes tt.e mesentery in tr.o aault v.hici: Co ri 

 calls the "haup tnesent erium" ana which Eenham names the "oesoph- 

 ageal" and "rectal" meaent '^•^i'^s. Mesenteries are present in the 

 ver;,' youn,'; Phoronis (just after tiie completion o -^ the .w^^ti^nor- 

 rhosis) which are founa in the exact position that one would ex- 

 pect the ventral mesentery o "f^ the Actinotrocha to assume after 

 metamorphosis, Ikeda's fiy;res indicate that he considers ti:e 

 lor4:i tudinal miesent eries of the very younj_^ Phoronis to be the 

 same a.6 the veiitral mesenter-\' oi' the Actinotrocha, for he j-,ives 

 them the sajne nairie, 



I cojinot offer any observation on the orajjiji o f" the lateral 

 mesenteries o-^the adult except that they are not present in the 

 very youn,: Phoronis that 1 have examined. They unaoubtedly arise 

 later in the life fii story, 



^J'9Jl''3-S^t-^P?-y^SS'}S^V}-P-Jr-^ Thi y structure is not present in the 

 Actinotrocha Gpecies, A., so 1 am no t able to t^ive any informa- 

 tion on the subject. It s'^en.t; to be the general opinion araong 

 those who have studiea the metamorphosis that it uoes not persist 

 as an orgaji in the adult. 



Digestive Areas:- V/hile these organs persist for some lit- 

 tle time after metamorphosis, they are not eviaent as organs in 

 the adult Phoronis architecta. 



