CILIA TA 89 



nodal points containing dark, strongly refractile granules in 

 some abundance. Where the protoplasm borders on the 

 large vacuole (v), which I believe to be the contractile 

 vacuole, although I did not observe its pulsations, it again 

 forms a very distinct radiate layer, which is separated from 

 the vacuole by a dark margin. It is worthy of note that 

 here the layer of meshes following immediately under the 

 alveolar layer also shows a radiate arrangement. We thus 

 have the same state of things before us as has already been 

 described by Schewiakoff and myself for other Ciliata (see 

 Protozoa, p. 1264, and Schewiakoff, 1889). 



The alveolar framework of the internal protoplasm was 

 in a state of incessant wave-like movement to a-nd fro, on 

 account of which the dark granules also appeared as if in a 

 state of vibration. 



I was able, moreover, to convince myself of the reticular 

 nature of the living endoplasm in strongly compressed speci- 

 mens of Paramcecium caudatum and Stylonycliia pustulata, 

 as well as to make out the alveolar layer in the living 

 condition. The reticular structure of the protoplasm was 

 very distinct in preparations of Paramcecium bursaria, which 

 had been killed in a mixture of picro-sulphuric and osmic 

 acid, and had hence become dark -brown in colour. Plate IV. 

 Fig. 6 represents a small portion of the cortical protoplasm 

 with the thickly-packed zoochlorellae (z). Here the radiate 

 arrangement of the meshes round the surface of the zoo- 

 chlorellse is especially noteworthy. 



In Paramcecium caudatum and putrinum, in Cydidium, 

 and also in Zoothamnium mucedo Entz, which I was able to 

 observe in Naples, I was struck by the fact that the entire 

 endoplasm is crammed with an immense number of minute 

 bodies. These bodies are present in such masses that be- 

 tween them only one or a few meshes of endoplasm remain 

 (see Plate IV. Fig. 7 of Stylonycliia, Fig. 8 & of Paramcecium 

 caudat.) They can be easily isolated by compressing the 

 Infusoria till they burst. I have not determined their size, 

 but reckon it at about I //, in diameter. In Zoothamnium 

 much larger ones also occurred. For the most part they are 

 roughly spherical, more rarely oval or elongated. When 



