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UNITED STATES NATIONAL MUSEUM BULLETIN 215 



Umbilical Aperture 



Extraumbilical-umbilical Aperture Equatorial Aperture 



Spiroumbilical Aperture Relict Apertures 



Areal Supplementary Single Sutural 



Apertures Supplementary Apertures 



Multiple Sutural 

 Supplementary Apertures 



Infralaminal 

 Accessory Apertures 



Figure 5. — Apertural types in planktonic Foraminifera. 



Intralaminal 

 Accessory Apertures 



with many openings along the sutures, as in 

 Candeina. They may be restricted to the spiral 

 side as in Truncorotaloides, restricted to the um- 

 bilical side as in Roicdipora, or present on both 

 sides as in Candeina. 

 Accessory apertures: The accessory apertures do 

 not open directly into the primary chambers, but 

 are openings in or under the accessory structures 



(i.e., bullae and tegiUa) found in the planktonic 



Foraminifera. 



Infralaminal accessory apertm'es. One or more 

 openings along the margins of the accessory 

 structm^es, e. g., Catapsydrax, Globigerinita. 



Intralaminal accessory apertures. Openings, usu- 

 ally multiple, which pierce the accessory struc- 

 tiu"es, e. g., Rugoglobigerina. 



