424 



H. BOSCHMA. 



mesentery. When food in great abundance has been offered to 

 the polyps these parts ingest a great deal of it; when only 

 moderate portions of food are given nearly all the food is ingested 

 in the zone next to the marginal part. During a few days the 

 distribution of the black particles in the mesenterial filament? 

 does not alter perceptibly (Fig. i) ; afterwards (about 5 days after 



m 



EXPLANATION OF THE TEXT FIGURE. 



Transverse section of the free extremity of a mesentery of Astrangia dance, 

 circa 2 days after the feeding of the polyp with a mixture of crab meat and India 

 ink. Fixation 5 per cent, trichloracetic acid; stained with hematoxylin Delafield, 

 d, digestive region of the mesenterial filament, crowded with black particles; g. 

 glandular part of the mesenterial filament; gc, gland cells; m, mesogloea; n, 

 nematocysts. X 3- 



feeding) the black particles gradually disappear from the digestive 

 part of the mesenterial filaments. On the seventh day after the 

 feeding usually the black particles have completely vanished from 

 the digestive organs. 



Crab meat mixed with ammonia carmine gave approximately 

 the same results: during a number of days after the feeding the 

 digestive zone of the mesenterial filaments then contains a 

 quantity of red vacuoles. 



Another series of feeding experiments was made with crab meat 

 mixed with litmus. This mixture keeps its blue color whilst 

 remaining in the gastric cavity, but after the food has been 

 ingested in the mesenterial filaments the latter acquire a red color. 

 This change of color is clearly visible in the living animal through 

 its transparent tissues. Microscopic examination of a mesen- 

 terial filament soon after feeding proves that in the digestive zone 

 a large number of red vacuoles of different size are present, whilst 

 particles of litmus lying against the mesenterial filaments but not 

 yet ingested have retained their blue color. Consequently the 



