70 FORAMINIFERA 



FAMILY 4. SACCAMMINIDAE 



Test free or attached, composed typically of a single chamber 

 or occasionally with chambers of the same sort loosely united; 

 wall lined with chitin, the exterior of agglutinated material of 

 various sorts, sand grains, sponge spicules or other f oraminif eral 

 tests; aperture usually single, of various shapes. 



KEY TO THE GENERA 



I. Test without a definite aperture, usually free. 



A. Wall of coarse material. 



1. Test of a single globular chamber Pscunmosphaera. 



2. Test of a colony of similar globular chambers.. . .Sorosphaera. 



B. Wall of fine whitish material; test polygonal Storthosphaera. 



II. Test with a definite aperture. 



A. Test free, usually with brownish cement. 



1. Wall of coarse material. 



a. Aperture terminal, usually with a neck. 



( 1 ) . Test globular Saccammina. 



(2). Test flask-shaped or pyriform; neck without a lip. 

 (a). Wall with little chitin, thickly encrusted. 



Proteonina. 

 (b). Wall largely chitin, thinly encrusted. 



LagenamTnina. 

 (3). Test flask-shaped, with a flaring lip.. . .Lagunculina. 



b. Aperture terminal, without a neck, and at the broad end 



of the test Urnulina. 



c. Aperture not terminal. 



(1). Curved, in a depression Millettella. 



(2). Rounded, not in a depression Marsupulina. 



2. Wall of fine material. 



a. With two apertures close to one another. 



Ammosphaeroides. 



b. With numerous remote apei-tures, usually with necks. 



Thurammina. 



3. Wall entirely chitinous Pseiidarcella. 



B. Test free, usually whitish. 



1. Aperture rounded. 



a. Wall of material without definite arrangement, spicules 



few Pelosina. 



b. Wall largely of spicules, definitely arranged. . . Techyiitella. 



2. Aperture elongate, narrow Pilulina. 



