23 (22) Rigid test 24 



24 (23) Test is compressed; chambers are broader than high. Length 0.35-0.42 mm. a, Side view; ra a 



b, top view Reophax arcticus 



24 {23) Test is circular in transverse section; wall is rough owing to relatively large sand grains 25 



X75 



25 (24) The last several chambers are nearly equal in size. Length 0.65-0.90 mm Reophax scorpiurus 



X25 



25 (24) Final chamber makes up most of the test. Length 1 .3-1.7 mm Reophax curtus 



26 (22) Test is composed entirely of coiled chambers; aperture is a transverse slit in 

 the middle of the apertural face; pores at the base of the coil constitute sup- 

 plementary apertures; wall is finely arenaceous, smoothly finished. Length 

 about 0.4 mm. a, Side view; b, edge view Ammoastuta inepta 



X100 



26 (22) Test has an initial coil and an uncoiled part 27 



11 



