48 PEOCEEDINGS OF THE NATIONAL MUSEUM vol. 80 



Family CASSIDULINIDAE 

 Subfamily Ceratobulimininae 



Genus PULVINULINELLA Cushman, 1926 



PULVINULINELLA VELASCOENSIS (Cushman) 



PLATE! 14, Figures 6 o-c 



TruncatuUna velascoensis Cushman, Contr. Cushman Lab. Foram. Res., vol. 1, 

 pt. 1, p. 20, pi. 3, fig. 2, 1925; Bull. Amer. Assoc. Petr. Geol., vol. 10, p. 606, 

 pi. 21, fig. 8, 1926. 



Rotalia velascoensis White, Journ. Pal., vol. 2, p. 290, pi. 39, figs. 5 a-c, 1928. 



Test nearly bilaterally symmetrical' with a very thin, broad keel; 

 chambers all visible from the dorsal side, only those in the last- 

 formed coil from the ventral side, about 10 chambers in the last- 

 formed coil, fewer in the earlier ones; chambers distinct, especially 

 from the ventral side ; sutures on the dorsal side raised and confluent, 

 on the ventral side slightly depressed, curved; wall smooth on the 

 ventral side, the dorsal side with an excavated area over each cliam- 

 ber ; aperture elongate, narrow, on the ventral side of the last-formed 

 chamber nearly in the axis of coiling. Diameter, up to 1.2 ; height^ 

 0.4 mm. 



This is a common sj^ecies in the Velasco formation of Mexico and 

 occurs in typical form in the Cretaceous of Trinidad. The position 

 of the aperture places this species in the genus Pulvinulinella. 



PULVINULINELLA ALATA (Marsscn) 

 Plate 15, Figures 1, 2 



Discorbinn alata Marsson, Mitth. Nat. Ver. Neu-Vorpommeni Riigen, vol. 10, 



p. 165, pi. 4, figs. 33 a^d, 1878. 

 PulvimcUna alata Franke, Abb. Preuss. Geol. Landes., vol. Ill, p. 185, pi. 17, 



figs. 8 ff-c, 1928. 

 Gyroidina fiorealis White, Journ. Pal., vol. 2. p. 298, pi. 40, figs. 3 a-c, 1928. 



Test plano-convex, the ventral side very strongly convex, dorsal 

 side flattened or even slightly concave except in the center, which is 

 slightly raised, periphery strongly keeled and developing a flat carina, 

 which is often broken; chambers usually about six or seven in the 

 last-formed Avhorl, distinct, inflated on the ventral side, but very 

 slightly, if at all, on the dorsal side; sutures distinct, those of the ven- 

 tral side sigmoidally curved and very slightly depressed, those of the 

 dorsal side strongly oblique, distinctly limbate ; wall smooth, but dis- 

 tinctly perforate; aperture ventral close to and parallel with the 

 peripheral margin. Diameter, 0.9-1 ; height, 0.5 mm. 



This species was originally described by Marsson from the Upper 

 Cretaceous of the Island of Riigen. It has also been recorded from 



