EUPLOTES WORCESTERI: I. 305 



possibly contractile, has notliing to commend itself to further consider^ 

 ation. 



The granules are not dissolved by strong or dilute acetic, hydrochloric, 

 or nitric acids, nor bj' absolute or dilute alcohol. Gram's solution of 

 iodine and potassium iodide causes no change of color either in the cold or 

 after heating. Iv'o change of color occurs after treatment with iodine, 

 heating, and addition of strong sulphuric acid. Dilute osmic acid 

 blackens the granules instantly. Absolute alcohol used after osmic acid 

 does not dissolve them; absolute alcohol and ether, after treatment with 

 osmic acid, dissolves the granules. 



From these tests it seems to be clear that the granules are fatty in 

 their nature. The animals of depressed or starving cultures sometimes 

 have few or none of these granules, while in vigorous cultures all the 

 Euplotes have very numerous and well-developed ones. It appears then 

 to be a fair conclusion that these peculiarly arranged granules of the 

 ectosarc constitute a supply of reserve fatty food-substance. 



Endosarc. — The endosarc presents a most irregular structure, differing 

 according to the condition of the animal, whether full fed or starved, and 

 the nature of the food. It is well to remember that a large part of what 

 is commonly called endosarc is a mechanical mixture of protoplasm, food 

 in various stages of digestion, water, and indigestible particles or excreta. 

 In addition to the finely granular protoplasm which sections always 

 show, the endosarc of this Euplotes contains great numbers of fibers. 

 These are visible when the protoplasm has been crushed and torn during 

 the process of sectioning and mounting. The constant motion of the 

 central portion of the endosarc prevents there being any definite visible 

 structural relation here. 



The animals of well-fed cultures usually show large numbers of 

 rounded, ovoid, or spherical granules, which are highly refringent, and 

 form a conspicuous feature of the living endosarc. These spherules are 

 unchanged by osmic acid, and are not dissolved by alcohol or ether, nor 

 b_y the two together, but they are dissolved instantly by very weak solu- 

 tions of nitric and hydrochloric acids and by strong acetic acid. They 

 appear, therefore, to be a sort of calcareous concretion, bearing a certain 

 resemblance to the crystals of calcium orthophosphate foimd in the 

 endosarc of Paramcecium. 



Ingestion and egestion. — The formation of a ball of food and its pas- 

 sage into the protoplasm is -very much the same in Euplotes as in such 

 a form as Paramcecium, except that there is no visible layer of water 

 surrounding the food; no food-vacuole Can be observed inside the body. 

 The food mass appears to be in direct contact with the protoplasm, and 

 while undoubtedly some water is swallowed with the food, there is not 

 enough of it to be visible. 



After entering the body the food mass is caught up by the circulating 

 stream of protoplasm, which carries it forward, and then in a circle. 



