144 



I. IKEDA. 



Inclosed in the cytoplasm are, as is well known, numerous yolk-like 

 spheres of various siz3s (fig. 1, a, b).* They are not crowded together, 

 but are scattered throughout the cellbody. In the fresh state they are 

 colourless, opaque and very weakly refractive. The larger of them may 

 be nearly as large as, and sometimes even larger than, the blood" 

 corpuscle ; whereas the smaller may be as small as the nucleus of the 

 same. All the smallest (fig. 1, b) are simple elementary bodies, which 

 cohering in varying numbers, seem to compose the larger spheres (a). 

 These are then, as are in fact apparent from their structure, to be con- 

 sidered as conglomerates of the smaller elements. Osmic acid blackens 

 the spheres, as when the tissue had been fixed with Flemming's fluid. 

 Iron-hsematoxylin stains them so deeply that the conglomerate nature 

 of the larger ones becomes obscured. Very goad preparations were 

 obtained by using corrosive-sublimate solution as the fixing reagent and 

 by staining with Delafield's hematoxylin in combination with either 

 eosin or Congo-red. Eosin invariably stains the spheres very deeply. 



As will be shown, the above described spheres disappear — are 

 evidently used up — -during the development of the sexual cells, the epithel- 

 ium itself dwindling away and finally likewise disappearing to give place 

 to the genitial glands. Taken in all, it appears to me exceedingly prob- 

 able, if not ndubitable, that the spheres are to be looked at in the light 

 of a nutrient substance in reserve, which is needed for the development 

 of the sexual products. Whatever they may be in chemical respect, 

 physiologically they seem to be much the same as the fat. In accordance 

 therewith, the modified peritoneal cells containing them may without 

 impropriety be called the reserve-nutriment cells, or for the sake of 

 brevity, simply the nutriment cells. The layer formel of them may 

 conveniently be referred to as the nutriment layer. 



Cori found in P. psammophila the so-called spinale-bo:iies, first 



* Besides the yolk-like spheres here described, the cells in question contain in the 

 fresh state a number of minute, réfringent and reddish-yellow granules scattered in the 

 cytoplasm. After the tissue is fixed and preserved, they are no longer to be seen. I am 

 not in a position to decide whether they are pigments or a fatty matter. 



