18 (13) Apertures are at the ends of protruding nipples; wall is thin, very fine grained, 



parchmentlike. Diameter about 1 mm Thurammina papiltata 



18 (13) Apertures are at the ends of radiating arms; test has a discoid 

 center; wall is coarse and friable. Diameter exclusive of arms 

 2-4 mm Astrorhiza limicola 



19 (2) Test consists of two chambers — a spherical initial chamber and a long undivided 

 second chamber; coiling is planispiral; wall is fine grained; color reddish or yellow- 

 ish brown. Diameter about 0.30 mm Ammodiscus minutissimus 



X75 



1 9 (2) Test consists of more than two chambers 20 



20 (19) Chambers, in the later part of the test, are arranged in a row or rows 21 



20 (19) Chambers are arranged in a coil 35 



21 (20) Test is uniserial 22 



21 (20) Test is multiserial 30 



22 (21) Test is not coiled at the beginning , 

 22 (21) Test has a coiled beginning 



.23 

 .26 



23 (22) Test is flexible, minute, later chambers overhanging earlier ones. Length 0.30-0.55 



mm Reophax scottii 



10 



