ACANTHASCüS CACTUS. 157 



mentioned here. They are generally tolerably uniform in size 

 within a tliesocyte. In certain cases, however, I have found them 

 quite unequal in size, the larger ones appearing to have arisen 

 from the combination of several smaller ones. Further in certain 

 individuals I have not infrequently met with thesocytes in which 

 the spherules were apparently in the process of disintegrating 

 into irregular granules ; or in other cases, of dissolving into a 

 diffuse state. The diiferences in appearance may be partially due 

 to the drastic influence of the preserving reagents ; nevertheless 

 I believe that they may in general be taken as representing the 

 changes which the spherules, as a nutritive substance held in re- 

 serve, undergo by a natural physiological process before they are 

 consumed. And it would be but natural if we should find that 

 some thesocytes are quite or nearly quite devoid of the fat-like 

 contents as the result of consumption. As such thesocyte relics 

 I consider certain pale-looking cells which are now and then 

 found wherever thesocytes might be expected to occur. A few 

 cells of the kind in question are to be seen in the left upper 

 part of fig. 18, PI. XL They are of about the size of ordinary 

 thesocytes filled up with spherules. Probably they are of a more 

 or less collapsed shape. The faintly colored and finely granular 

 cytoplasm incloses a distinct .nucleus, while its external limit is 

 well-defined and is sometimes distinctly provided with an envelop- 

 ing membrane. The cells can scarcely be viewed in the light 

 of early thesocyte stages before the formation of the spherules ; for, 

 there exist other cells which alone can be viewed as inceptional 

 thesocytes, viz., those very much smaller than full-sized thesocytes 

 and which already contain the spherules though yet in quite a 

 limited number. 



I may here add that in some instances the fat-like spherules 



