INTRODUCTION 



The foraminifera have come to have a place of economic im- 

 portance as v^ell as of general scientific interest. Their use in 

 geologic correlation especially as an aid in determining subsur- 

 face structures in connection with petroleum investigations has 

 become wide spread. 



At the present time there is no general account of the fora- 

 minifera in English since that published by Chapman in 1902 

 and that is now out of print. To fill this need in an outline form 

 rather than in detail the present volume is offered. The pre- 

 liminary paper entitled : "An Outline of a Reclassification of the 

 Foraminifera" (Contrib. Cushman Lab. Foram. Res., vol. 3, pt. 

 1, 1927) published a year ago has met with such an unlooked 

 for favorable reception that the edition is practically exhausted. 

 The more complete volume here presented is a fulfillment of the 

 statement made in the earlier paper. It has been necessary to 

 see and study certain of the older collections containing type 

 specimens. On these specimens depends the status of many of 

 the earlier species and the genera based upon them. Fortunate- 

 ly these collections are for the most part splendidly preserved, 

 and it has therefore been possible to settle many of the mooted 

 points by an examination of the type specimens this last summer. 



To those in charge of these collections in various European 

 museums and universities, I am indebted for many courtesies 

 extended to me in pursuing these studies. As a result I have 

 seen actual types of nearly all those species which have 

 become genotypes and in the others in almost all cases seen 

 topotype material. As a result of these studies it is now possi- 

 ble to know very definitely what should be the characters in 

 many of the genera where questions have arisen and which 

 might have been easily settled by a glance at the type specimens. 



