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BULLETIN 104, UNITED STATES NATIONAL MUSEUM 



extending back, finally meeting and in most of the chambers forming 

 annuli ; aperture consisting of a single row of pores along the periphery 

 of the test. 



Diameter, up to 2.5 mm. 



This species is common at some localities, and in early life is an 

 attached form afterwards becoming free. The development has 

 already been discussed in part 6 of Bulletin 71. 



Sorites marginalis — Material examined 



Genus AMPHISORUS Ehrenberg, 1838 



Amphisorus Ehrenberg, Abhandl. k. Akad. Wiss. Berlin, 1838, p. 130. — 

 CusHMAN, Special Publ. No. 1, Cushman Lab. Foram. Res., 1928, p. 221. 

 Orbitolites (part) of Authors, (not Lamarck). 



Genoholotype. — Amphisorus Jiemprichii Ehrenberg. 



Test discoid, planispiral in the early stages, at least of the micro- 

 spheric form, later annular, completely divided into chamberlets; 

 typically in two layers, those of each annular chamber communicating 

 with the adjacent ones of the preceding and succeeding annular cham- 

 bers and those of the two layers communicating; wail imperforate 

 except in the very earliest chambers; apertures in a double, alter- 

 nating line along the periphery. 



Miocene to Recent. 



Bradyella Munier-Chalmas is probably a synonym of Amphisorus. 



