9 8 



BIOLOGICAL LECTURES. 



FIG. 7. 



vary in different genera and even species. In Nephelis and 

 some species of Clepsine several large vacuoles (v) lie in the 



centre of the cell and even 

 flow together in different 

 places. The periphery of 

 the cell is crowded with 

 smaller vacuoles (v), which 

 also flow together in vari- 

 ous directions, thus form- 

 ing an irregular network of 

 canals (Fig. 8). In other 

 species of Clepsine (biocu- 

 lata, nepheloidea, parasita, 

 Hollensis) we notice a 

 very peculiar structure. 

 The centre of the cell 

 is occupied by a dense, 

 irregularly shaped mass 

 (um\ which stains deeper 

 than the surrounding cyto- 

 plasm. Under a very high 

 magnification this mass 

 shows itself to be com- 

 posed of innumerable very 

 small vacuoles closely 

 pressed together and with 

 little granules in the cen- 

 tre (Fig. 9). I attribute 

 the deeper stain of this 

 mass to the fact that the 

 cytoplasmic threads are 

 closely wedged in between 

 these vacuoles. In the 

 cells next to these we 

 notice that the vacuoles of 



FIG. 9. 



this mass flow together in 



rows and plates, and that even the central masses of two 

 neighboring cells unite (Fig. 10). 



FIG. 8. 



