1 8 SlDEBOTTOM, Foraminifera from the Island of Delos. 



this peculiarity is present, but to what extent, it would 

 be hazardous to say. It looks as if the protoplasm 

 preferred to make a free opening in the wall of the 

 chamber (and a more central one in regard to the 

 new chamber to be formed) rather than to exude 

 itself through its ordinary minute mouth when the time 

 for extension of premises arrived. I suppose we shall 

 have to wait until the life history of some of the species 

 is written before the true explanation can be arrived at. 

 Brady ('84, p. 563) has drawn attention to this peculiarity 

 in some of the tests of P. angnsta, Egger (a small, 

 starved, deep-water form), but I do not remember seeing 

 any references by him to other species showing the same 

 phenomenon. 



Carpenter, in the " Introduction to the Study of the 

 Foraminifera" ('62), p. 168, says, " It is a curious fact that 

 when an outer 'wild-growing' segment extends itself 

 over the whole of the preceding series, its cavity com- 

 municates, not merely by the usual radiated aperture, 

 with the antepenultimate chamber, but also by a double 

 row of openings with all the chambers which it overlaps. 

 It is difficult to suppose that these openings existed 

 anteriorly to the overgrowth ; and we can scarcely 

 account for their presence in any other way, than that 

 they have been formed de novo by absorption." 



