18 ILLINOIS BIOLOGICAL MONOGRAPHS [228 



alone, and that constant and steady increase in the withdrawal of the cell 

 sap accounts for the apparent atrophy, 



Pyxinia mohuzzi (Leger and Duboscq, 1902) possesses a long tongue- 

 like epimerite (Fig. 98) which extends longitudinally through the pene- 

 trated cell as far as the mesothelial layer of the intestine. The penetrated 

 cell seems to be uninjured by this epimerite and the authors think the 

 animal absorbs blood from the capillaries in the mesothelium by means 

 of the epimerite. 



The Dactylophoridae, e. g., Nina gracilis Grebnecki (Fig. 30), have 

 epimerites with many long radices, which Leger and Duboscq (1902: 

 458) state penetrate at many places several adjoining cells and probably 

 function as an apparatus for nutrition. Many genera, Beloides, Pyxinia^ 

 etc., have a long central style in the epimerite which punctures the cyto- 

 plasmic vacuoles and absorbs the cell sap directly. 



Siedlecki (1901:98) says the long filaments from the epimerite of 

 Nina gracilis penetrate into the epithelial layers between the cells and do 

 not puncture the cells themselves, as Leger and Duboscq think. 



Minchin (1912) says that the cytoplasm of the cell is absorbed by 

 the parasite, which I infer to mean used as food, and that ' ' when the cy- 

 tozoic phase is past and the host cell exhausted, the parasite drops off, 

 shedding its epimerite." 



The present writer agrees with Leger and Duboscq and with Minchin 

 that there is absorption through the epimerite. When a free cephalont is 

 stained, its epimerite is seen to contain considerable endoplasm and not to 

 be merely an ectoplasmic structure filled with sap. Moreover, stained 

 sections of parasitized epithelium reveal the presence of attached cepha- 

 lonts which are transparent or nearly so and which do not absorb the 

 stain. Living material often contains large numbers of free cephalonts 

 which contain but very little protoplasm or none whatever. These facts 

 lead to the theory that the epicyte is not yet in physiological condition to 

 absorb fluids from the intestine but that all such absorption takes place 

 through the epimerite. Whether or not the epimerite possesses an epicyte 

 of different structural character from that of the rest of the body is not 

 known. It does, however, possess a very delicate, fragile, highly per- 

 meable layer susceptible to slight changes in osmotic pressure. The sug- 

 gestion may be made that because the chemical constituency of the fluids 

 in the lumen of the intestine and in the epithelial cells is obviously dis- 

 similar, the parasite may or may not be able to absorb either of these 

 fluids through the epicyte ; and if they are absorbed may not be nourished 

 by one of these ingested fluids. The fact that the epimerite often con- 

 tains protoplasm while the rest of the cephalont is still transparent or 

 nearly so and that the cephalont remains nearly transparent as long as 

 the epimerite persists, leads to the theory that whereas at first all the ab- 



