THE FORAMINIFERA 



The arrangement of the chambers which succeed varies in 

 different specimens. In some (as in Fig. 57, A) a succession of 

 about six subdivided " heterostegine " chambers follows, which 



Fio. 57. 



Cydodypem carpenteri, Brady, m, a complete test, x 8. A, central region of a decalcified 

 specimen of the megalospheric form, x 85. B, central region of a section of the test of the 

 microspheric form, x 50. The canal system is not seen in these figures. The figures 1 and 9 

 in B mark the first and last of the undivided chambers, 20 is a heterostegine chamber, and 25 

 the first of the annular chambers. 



become more and more embracing, until they extend completely 

 round the previously formed chambers. The annular arrangement 

 once attained is continued, though not without irregularities of 

 growth, till the test is complete. The mode of communication of 



