X50 



106 (105) Surface is smooth; umbilicus has one or more plugs. Diameter 0.25- 



0.50 mm. a. Side view; b, edge view Elphidium advena 



106 (105) Surface looks sugary; umbilicus lacks plugs. Diameter 0.40-0.60 



mm. a. Side view; b, edge view Elphidium margaritaceum 



X50 



X150 



107 {105) Wall is coarsely porous and rugose. Diameter 0.20-0.32 



mm. a. Side view; b, edge view Elphidium gunteri 



107 (105) Wall is finely perforate and smooth 108 



108 (107) Septal bridges are regular 109 



X75 



108 (107) Septal bridges are irregular; sutures are crenulated, especially so 

 toward the umbilicus; test is thickest through the umbilical area. 

 Diameter 0.40-0.75 mm. a, Side view; b, edge view Elphidium clavatum 



35 



