48 



specified above the anus alone is developed from the blastopore, 

 and the month is formed in front of it. This is also characteristic 

 of vertebrate development. Chaetognatha may be said to stand 

 more directly in relation' to the " Hydrocoela." 



This raises the question of the homologies of structural elements 

 related in the one case to a stomodeal blastopore, and in the other 

 to a proctodeal blastopore. 



These are matters which need not be discussed here. I content 

 myself with saying that Phoronis must be placed amongst the 

 groups of Invertebrates which present a stomodeal blastopore, 

 and by drawing attention to the fact that the metasome of Phoronis 

 is directly homologous with the foot of MoUusca (and Caldwell 

 was justified in calling it by that name) and with the part of the 

 body of the GephjTea intervening between the mouth and the 

 anus, the outgrowth of v/hich gives rise to the greater part of the 

 body of the adult. 



Reference has been made to some of the papers, but a full 

 bibliography of the subject will be found in de Seh^s Longchamps' 

 account of Phoronis in Fauna u. Flora d. Golfes v. Neapel, 1907, 

 monograph 30. 



