258 FOKAMINIFERA 



Genus TRIFARINA Cushman, 1923 



Plate 36, figures 21, 22; plate 37, figure 23 

 Genoholotype, Trifarina bradyi Cushman 



Trifarina Cushman, Bull. 104, U. S. Nat. Mus., pt. 4, 1923, p. 99. 

 Rhabdogonium of authors (not Reuss). 

 Triplasia of authors (not Reuss). 



Test elongate, triangular in transverse section ; the early 

 chambers in an irregular spire or triserial, later ones becoming 

 uniserial ; wall calcareous, perforate ; aperture terminal in the 

 adult, rounded, with a short neck and phialine lip and internal 

 tube. 



Cretaceous ( ?) Eocene to Recent. 



See Cushman, Trifarina in the American Eocene and Else- 

 where (Contr. Cushman Lab. Foram. Res., vol. 1, 1926, pp. 

 86-88), 



Genus DENTALINOPSIS Reuss, 1860 



Plate 36, figure 31; plate 37, figure 24 

 Genoholotype, Dentalinopsis semitriquetra Reuss 

 Dentalinopsis Reuss, Sitz. k. bohm. Ges. Wiss., Jahrg., 1860, p. 91. 



Test uniserial ; the chambers in a generally straight or slightly 

 curved linear series, early chambers angled and triangular in 

 section, later ones rounded ; wall calcareous, perforate ; aperture 

 rounded, terminal. 



Cretaceous. 



Genus SPORADOGENERINA Cushman, 1927 



Plate 36, figures 32, 33; plate 37, figure 21 

 Genoholotype, Sporadogenerina flintii Cushman 



Sporadogenerina Cushman, Contr. Cushman Lab. Foram. Res., vol. 2, 

 1927, p. 95. 



Test with the early chambers uvigerine, especially in the 

 microspheric form, later ones irregularly uniserial and elongate ; 

 aperture changing from a regular terminal position to one or 

 more definite openings at the side of the chamber. 



Recent. 



The Buliminidae form a very closely-linked group, the inter- 



