406 E. p. CHURCHILL, JR. 



Blegvad ('15) found that the invertebrates on the sea-bottom 

 in Danish waters hve on detritus and to a lesser extent on plank- 

 ton. He does not corroborate Putter's theory but on the con- 

 trary thinks that the latter did not allow enough for the quantity 

 of detritus. 



Ester ly ('16) found that in pelagic copepods the amount 

 of food that is indicated by the intestinal contents is 'surpris- 

 ingly small.' He suggests however that it is probable that much 

 of the food of these forms consists of organisms without shells 

 and which do not leave recognizable remains in the intestine. 

 Further careful investigation he feels is necessary before Flit- 

 ter' s theory is accepted. 



Lund^ found that if Bursaria are kept in a weak soap solution 

 they will absorb fat from such solution through their body walls. 



The present author, in 1915, published a paper in which 

 were set forth the results of the earlier steps of his investigations. 

 Fat was selected for the initial experiments as it' is most easily 

 traced histologically. Following the method of Lund, olive oil 

 was saponified and the mussels kept in weak solutions of the 

 resulting soap. In some cases the solutions were stained with 

 Sudan III. Briefly stated, it was found that the mussels ab- 

 sorbed fat from the solutions to a marked extent. This was 

 transported over the body by the plasma of the blood and by 

 the corpuscles. Several of the experiments went far toward 

 proving that some of the fat was absorbed directly by the cells 

 of the gills, mantles and foot. 



The present paper discusses the results of the continuation 

 of the series of investigations. Further work was done on 

 the absorption of fat using a commercially prepared soap in- 

 stead of the saponified oil. The absorption of protein was 

 studied somewhat extensively and some efforts were made to 

 ascertain the facts in regard to the absorption of starch. 



The author wishes to express his obligations to Dr. Caswell 

 Grave, at whose suggestion the work was undertaken, for ad- 

 vice and aid given throughout the course of the investigations: 



^ Dr. Lund's results are not yet published. 



