INTRODUCTION. 



This paper is the fourth part of a work the intent of which is 

 to describe and illustrate the Foraminifera of the Atlantic Ocean, 

 especially those species which have occurred in the waters adjacent 

 to the shores of the United States, including the whole of the Gulf 

 of Mexico and the Caribbean Sea, that being the area in which most 

 of the work of the vessels of the United States engaged in dredging 

 work has been done. This part includes onl}- the family Lagenidae, 

 The first part, issued in 1918, included the family Astrorhizidae. The 

 second part, issued in 1920, included the family Lituolidae. The 

 third part, issued in 1922, included the family Textulariidae, The 

 fifth part will be devoted to the families Chilostomellidae and Globi- 

 gerinidae, and further volumes will take up the remaining families of 

 the Foraminifera as they are represented in the Atlantic Ocean. 



Joseph Augustine Cushman. 



