X25 



10 (3) Test is spherical, lacks an aperture; wall is thick, consisting of matted sponge 



spicules. Diameter 0.70-1 .00 mm. Broken section Crithionina pisum 



10 (i) Test has one or more apertures 1 1 



1 1 (10) Test has one aperture 12 



1 1 (JCf) Test has two or more apertures 13 



12 (11) Aperture is simple 14 



12 (H) Aperture is at the end of a neck 15 



13 (//) Test is an elongate tube open at both ends 17 



13 (11) Test is generally globular 18 



14 (12) Aperture is usually obscured by mud filling; wall is 

 thin, rigid, consisting of a single layer of large sand 

 grains neatly fitted together. Diameter 0.60-1.00 mm. 

 a. Exterior; b, broken section Psammosphaera fusca 



X40 



X50 



14 (12) Test is elongate subspherical; aperture is a round opening; wall is flexible, outer 

 layer consisting of fine sand. Diameter 0.40-0.50 mm. a, Side view; b, 

 top view Saccamminal sp. 



15 (12) Wall is coarsely agglutinated 1^ 



8 



