252 SYSTEMATIC PALEONTOLOGY 



with straight depressed septa between them and with the margin slightly 

 lobulated at their extremities. The inferior surface is flat or nearly 

 so; superior side convex and several (three?) convolntions indistinctly 

 visible. 



Septal lines rather sharply and gracefully curved and less definite as 

 the primordial chamber is reached, which makes it difficult to tell how 

 many chambers are present. Peripheral view a definite cone and aper- 

 ture lying underneath the margin. Shell is of small size but is very 

 abundant in the Lower Eocene. 



This species is found in the Chalk of Maastricht (Parker and Jones), 

 the Eocene of Paris (Terquem), etc. 



It is a shallow-water foraminifera as is proved by the Challenger 

 expedition which obtained the form at 420 fathoms (Ascension Island 

 small forms), 350 fathoms off the coast of South America, at from 

 two to ten fathoms at Port Jackson, Australia, and in the Bermuda 

 coral sands. 



Occurrence. — Aquia Foemation. Upper Marlboro. 



Collection. — Maryland Geological Survey. 



Genus TRUNCATULINA d'Orbigny. 



Teuncatulina lobatula (Walker and Jacob). 



Plate LXIV, Fig. 3. 



Nautilus lobatulus Walker and Jacob, 1798, Adam's Essaj's (Kanmacher's Edit.), 



p. 642, pL xiv, fig. 36. 

 Truncatulina lobatula Brady, 1884, Chal. Rept., voL ix, p. 660, pi. xcii, flg. 10; 



pi. cxv, tigs. 4, 5. 

 Truncatulina lobatula Bagg, 1806, Bull. 141, U. S. Geol. Survey, p. 93. 

 Truncatuli7ia lobatula Bagg, 1898, Bull. Amer. Pal., No. 10, p. 35. 



Description. — Test plano-convex, moderately vaulted; last volution 

 consisting of seven, eight, or nine chambers with slightly depressed 

 septa; septa more curved upon the superior (flat) surface; aperture a 

 small, neatly-shaped arch at the margin of the ultimate segment. Diam- 

 eter, 0.6 mm. 



Truncatulina lohaiala shows great variation. Professor Brady con- 

 siders that the more convex varieties merge into Truncatulina refulgens, 



