96 



THE FORAMINIFERA 



speak of their two ends as inner and outer the former directed 

 towards the concave side of the spire, the latter towards the 

 convex side. While they are simple at their outer ends, the 



Tests of Orbic-ulina adunca, 

 F. and M. a-b, young speci- 

 mens ; c-e, var. flabelUformis ; 

 f and (/, var. compressa; h, 

 var. adunca; B, full-grown 

 specimen of the inicrospheric 

 form of adunca. (g and B are 

 magnified about 8 times, the 

 other tests about 7 times.) 



chambers of young specimens of all varieties are equitant at their 

 inner ends, being produced on either side over the surface of the 

 already formed test, in alar prolongations (cp. Fig. 32). 



As growth proceeds, the chambers become more and more 



