78 E. P. CHURCHILL, JR. 



connective tissue or conveyed none to the liver, which is the 

 normal fat storing organ. If all the fat were absorbed by the 

 intestine it seems certain that the sections of one at least of the 

 mussels which had been kept in the fat solution for the short 

 periods would have revealed more fat within the deeper body 

 tissues than was found there. Wherever fat was found beneath 

 the outer epithelium of these mussels which had been in the 

 solutions for the short periods, much the larger quantity lay in 

 close proximity to that epithelium and the amount lessened to 

 zero toward the interior of the body. While the quantity of 

 fat beneath the epithelium increased with the length of the time 

 the mussel was kept in the solution, in all cases it was greatest 

 nearer the epithelium. Apparently the fat found lying closely 

 beneath the outer epithelium of the body had been absorbed 

 and passed into the deeper tissues by that epithelium and had 

 not come from the intestine. Also, if all the fat were absorbed 

 by the intestine and the blood did transport it almost entirely 

 to the outer epithelium it would seem most likely that the cells 

 of the side of the mantle next to the shell would receive at least 

 an observable amount. 



In order further to test the question of whether or not fat 

 may be absorbed from a fat solution by the epithelial cells of 

 the outer body walls of the mussel the following experiment w r as 

 performed. The valves of three adult mussels were wedged open 

 with bits of wood and the animals suspended on a wire rack 

 over the fat solution so that only the ventral parts of the mantle 

 and foot were immersed. The mouth and siphons were above 

 the solution so that it was not likely that any of the solution 

 could enter the intestine by way of the oral or anal openings. 

 One mussel was thus treated for 6 hours, the other two for 22 

 hours. They were compared with a fourth individual which 

 had not been in the solution, all four mussels having been removed 

 from the river only four or five days previous to the experiment. 

 One of the animals which had been treated as above for 22 

 hours did not have much fat throughout the deeper body tissues 

 but a moderate amount appeared in the epithelium of the part 

 of the mantle which had been immersed in the solution. The 

 other mussel which had been treated for 22 hours contained some 



