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PROCEEDINGS OF THE AMERICAN ACADEMY. 



is convinced by his histological studies that there are, however, no 

 permanent port-holes, or cinclides, in the body ■wall. He believes the 

 mesenterial filaments may make temporary apertures for themselves 

 in any part of the oral disk or wall of the column. When the fila- 

 ments are withdrawn the orifices close after a few minutes, and leave no 

 traces of their former existence. 



The eversion of the stomodaeum, accompanied by partial extrusion 

 of mesenterial filaments through the mouth, may follow a much less 



Figure 2. Diagrammatic vertical section through a contracted feeding 

 polyp. 



C, coclcnteron ; EZ, edge zone, folded over ; F, food particle ; MF, mes- 

 enterial filament, extruded ; 07), oral disk ; Sp, sphincter muscle, contracted; 

 St, stomodaeum, everted ; SC, supra-discal cavity ; T, tentacle. 



vigorous stimulus than the one just described. The reaction occurs 

 when a piece of filter paper soaked in diluted meat juice is dropped on 

 the oral disk. The latter becomes depressed, although the stimulus is 

 not sufficient to cause an overfolding of the edge zone. Under these 

 conditions the gullet may be seen to stretch toward the stimulating ob- 

 ject. If it reaches the filter paper, this may become partially inclosed 

 by the everted stomodaeum, and may lie for some time in contact with 

 the mesenterial filaments emerging from it, without being actually swal- 

 lowed. On comparatively few occasions have the bits of filter paper 

 been observed to pass into the coelenteron of the polyp. 



Reactions of the Tentacles. After sundown the tentacles of rose-coral 



