60 THE FOEAMINIFEKA 



careful consideration, such as the grouping together of 

 genera which are morphologically similar, but which 

 have differences of shell-structure. According to 

 these authors the shell-structure should be subordi- 

 nated to the form and manner of segmentation in 

 the animal, and this is in accordance with accepted 

 zoological principles. They divide the Foraminifera 

 into as many as thirty-seven families. To give an 

 example of the method used in classifying the group, 

 the Tribe Stichostegia (Eimer and Fickert) is divided 

 into, A, PSAMMATOSTICHOSTEGIA, including the Families 

 Hyperamminid.e (genera Hyperamumia, BeojjJiax, and 

 Hormosina) and Aschemonellid.e (genera Aschemo- 

 nella and Bamulina) : B, titanostichostegia, repre- 

 sented by the Family Nodosariid.e and genus 

 Nodosaria. In division A the test is arenaceous, and 

 in B it is calcareous. There is, however, no apparent 

 reason given for including JRamuUna in Division A, 

 since it is essentially calcareous. Very diverse forms 

 are here brought together, such as Ci-isteUaria, Ca.s- 

 sidulina, and Hagrai?ia, which are morphologically 

 distinct. 



The relationship of the different types of form in 

 Foraminifera is so complex and interwoven that, 

 from whatever standpoint we may approach the 

 subject, we are certain to meet with numerous 

 difficulties which prevent our making a satisfactory 

 classification. We may expect a more hopeful state 

 of things when further light has been thrown upon 

 the relation of environment to shell structure, and 

 dimorphism to specific forms. 



