IN THE MUD OF THE LEVANT. 41 



Creator has proceeded even in the production of 

 closely allied groups of objects. One fact noticed 

 by Milne Edwards, is, that in the oldest formed 

 cells of Eschara, the external lines of division 

 become obscure, if not altogether lost, by the 

 addition of new calcareous matter, in which the 

 large apertures alone are left visible — arranged 

 in quincunx, — and he justly contends that this 

 new matter could not have come from the interior. 

 Those who are familiar with Foraminifera, are 

 aware that the exteriors of the earliest formed cells 

 never lose their distinctness, by being thus exter- 

 nally invested with new matter, thickening their 

 parietes. 



Another fact is, that on submitting a Poly- 

 pidom to the action of nitrous acid, " a brisk 

 effervescence was visible immediately, and in 

 some minutes the cells became flexible and sepa- 

 rated from one another. Before treatmg them thus, 

 no distinct m-embrane was seen on the internal 

 walls of these cells, and when the nitrous acid 

 had destroyed all the calcareous carbonate on 

 which their rigidity depended, these same parietes 

 still existed^ and had not changed their form 

 much ; only they were formed now of a soft and 

 thick membrane, constituting a bag, in the interior 



