34 Bulletin io 328 



spiral manner and forming in our specimen about seven convol- 

 utions. The peripheral margin is broadly rounded. The lateral 

 surfaces are unlike, upon one the inner side of the coils are 

 marked by a large number of elliptical pits while the opposite 

 is somewhat granulated and apparently without the depressions. 

 The final convolution ends in a constriAed aperture, .slightly ec- 

 centric; diam. 0.52 mm. 



The above species resembles Spirillina margaritifera William- 

 son with this difference that in place of tubercles we have de- 

 pressions. I have only one specimen of this interesting form 

 but it is perfect and I have no hesitation in pronouncing it to 

 be new. 



Horizon and locality . — Miocene; Yorktown, Va. 



Genus DISCORBINA Parker & Jones. 



Discorbina bertheloti. 



Syn. Rosalina bertheloti d,Orh\^ny, Foram. Canaries, p. 135, pi. i, figs. 

 28-30, 1839. 

 Discorbina bertheloti Bagg, Bull. U. S. Geol. Surv., No. 141, 

 p. 92. 

 Test very compressed, carinate, finely punctate; spiral side ap- 

 proximately flat, reverse side low-convex; chambers depressed, 

 convex, numerous, margins slightly limbate; ultimate chamber 

 larger than the one preceding. The shell is quite similar to 

 Trnncatnlina lobaluta, but it is more depres.sed and the walls 

 are more finely perforate; diam. 0.42 mm. 



Horizon and locality . — Eocene; Woodstock, Va. 

 Geological distribution.— Q.XQX.Q.C.Q.OWS to Recent. 



Discorbina orbicularis. 



Syn. Rosalina orbicularis Terqueni, Anim. sur la Plage de Dunkerque. 

 pt. 2, p. 75, pi. ix, fig. 4, a, b, 1876. 

 Discorbina orbicularis Brady, Clial. Rep't, vol. ix, p. 647, pi. 

 Ixxxviiii, figs. 4-8, 1884. 

 Test small, nearly circular, superior side convex, inferior de- 

 pressed at the umbilicus and slightly concave; peripheral mar- 

 gin sharp. 



The superior chamber shows numerous, very much elong- 

 ated chambers which extend nearly half way around the shell 

 as they reach the peripheral margin. Upon the inferior side only 

 three or four segments are visible and these are marked by 



