220 FORAMINIFERA 



Test discoid nummulitoid throughout the growth, the growing 

 edge always peripheral; chambers involute, V-shaped, divided 

 into chamberlets. 



Upper Cretaceous. 



Genus MEANDROPSINA Munier-Chalmas, 1899 



Plate 31, figure 8 

 Genoholotype, Meandropsina vidali Schlumberger 



Meamlroiisina Munier-Chalmas, in Schlumberger, Bull. Soc. Geol. 

 France, ser. 3, vol. 27, 1899, p. 336. 



Test discoid, the growing edge variously meandering over the 

 flattened faces of the test; chambers with many chamberlets; 

 apertures rounded, in linear rows. 



Upper Cretaceous. 



Genus ARCHAIAS Montfort, 1808 

 Plate 31, figures 9, 10 



Genoholotype, Archaias sjnrans M.ontfoYt=Nautilus angulatus Fichtel 



and Moll 



Archaias Montfort, Conch. Syst., vol. 1, 1808, p. 191. 



Helenis Montfort, 1. c, p. 195 (genoholotype, Helenis spatosus MoNT- 



FORT = Nautilus aduncus Fichtel and Moll). 

 Ilotes Montfort, 1. c, p. 199 (genoholotype. Rotes rotalitatus Montfort 



=Nautilus orbicidus FiCHTEL and Moll). 

 Orhiculina Lamarck, Ency. Method., pt. 23, 1816, p. 468 (genotype, by 



designation, Nautilus aduncus FiCHTEL and Moll). 



Test in the early stages planispiral and lenticular, bilaterally 

 symmetrical, in later stages becoming flaring, even annular; 

 wall imperforate except in the very earliest chambers which are 

 perforate, divided into chamberlets ; apertures in several rows on 

 the apertural face. 



Miocene to Recent. 



Subfamily 3. Orbitolitinae 



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

 spheric form, later annular, in the simplest forms the chambers 

 only partially divided, completely so in the more complex forms; 

 apertures on the peripheral face. 



