202 \V. AllCHEtl. 



tinuity. In none of the Heliozoa is the high histological 

 development known in Radiolaria attained. 



2. Do the Heliozoa possess a " central capsule " or a struc- 

 ture homologous thereto ? Are the (median) rounded bodies 

 seen in their sarcode which have sometimes been regarded as 

 central capsule, sornetiraes as "inner vesicle" (Binnenblase, 

 Hack.), actually, indeed, organs so strongly demonstrative 

 of their Radiolarian nature ? 



Hertwig and Lesser answer these questions with a decided 

 negative. 



For my part, as mentioned, I feel they are quite right. 

 Nor has the nucleus alone been interpreted by various au- 

 thors as " central capsule " or " inner vesicle " for likewise 

 different regions of the body-mass itself have been so 

 denominated. 



In fact, to demonstrate the " unicellularity " of the Heliozoa 

 and the nuclear nature of the central body is at the same 

 time to show that the latter is not to be interpreted as central 

 capsule. 



3. Do the Heliozoa possess structures homologous to the 

 " yellow cells " of the Eadiolaria ? 



The yellow and green globules seen in many Heliozoa, bui 

 not confined to them, have been interpreted as equivalents of 

 " yellow cells." But Hertwig and Lesser rightly point out 

 they have no trace of cellular structure. In many cases they 

 differ only in size, not in colour or apparent nature, from the 

 minute granules distributed in the sarcode. 



Perhaps till more is known concerning them they had 

 better be simply regarded as pigment-granules ; some of these 

 attain sometimes a high colour, as in Pompholyxophrys 

 punicea. Hertwig and Lesser regard such as stored-up 

 nutriment ; but whether their colour in any way depends on 

 the food, or whether colourless at first, they afterwards 

 during the digestive process acquire a colour, they would 

 leave in abeyance. 



Originate as they may, Hertwig and Lesser in any case 

 rightly aver they are not cells, only constituents of the con- 

 tents of cells. 



To myself, their colour, average size, and usual quantity 

 seem to a certain extent specifically characteristic ; of two 

 kinds of them, the green and the yellow, I would take the 

 former to be " chlorophyll " (e. g. Acanthocystis turfacea, 

 Raphidiophrys viridis), the latter to be oil-globules (e. g. 

 Acanthocystis spinifera) ; very similar oily globules occur in 

 various animal and vegetable organisms and in diatoms. 

 Thus argue these authors that Heliozoa are no true Radi- 



