190 



On the Genera Salpingoeca and Polyceca. 



Polyceca is that the daughter individual in Polyoeca erects its 

 lorica on the mouth o£ the mother individual's lorica, instead 

 of swimming away and settling elsewhere. 



The excessively attenuate base of the lorica in Polyceca 

 _^ads one to imagine that the lengtii of stalk, in this form at 

 least, is due to the gradual increase in area of that part of 



Fig. 4. 

 Fur. 3. 



Fig. 3. — Division of P. dumosa (late stage). 



jpjo-, 4. — Diagram showing mode of formation of lorica in P. dumosa. 



the cell which is capable of secreting the material for the 

 formation of the lorica. A diagram (text-fig. 4) shows what 

 may happen in such cases. The successive stages of growth 

 of the cell are shown, and the secreting area in each case is 

 in continuous line, the rest of the cell-outline being dotted. 

 The form of the P. dumosa lorica suggests this mode of forma- 



