2 PKOCEEDIKGS OF THE NATIONAL MUSEUM vol.70 



chambers ornamented; test in transverse section roughly triangular, 

 the ventral side forming two sides and the apex of a triangle; wall cal- 

 careous, perforate; aperture elongate, nearly at right angles to the 

 edge of the chamber; surface smooth or ornamented with spines or 

 ridges. 



SPECIES FROM THE EOCENE 



EHRENBERGINA SEMMESI, new species 



Plate 1, fig. 1 



Test small, in front view somewhat rhomboid; chambers few, dis- 

 tinct; sutures very slightly depressed on the ventral side, not at all 

 so on the dorsal side; periphery with distinct, solid, acicular spines 

 on the angles of the last four chambers; surface smooth except the 

 margins of the last few chambers on the ventral side, which are 

 thickened; test in section biconvex; aperture elongate. 



Length 0.40 mm.; breadth with spines 0.50 mm. 



Holotype (Cushman Coll. No. 1595) from Alazan Clay, km. G6 on 

 Mexican Oil Fields R. R., Cazones River, Mexico, collected by D. R. 

 Semmes. 



This species has aheady developed the spinose character of the 

 periphery, more strongly so than others until the Pleistocene and 

 Recent species are seen. 



SPECIES FROM THE MIOCENE 



EHRENBERGINA SERRATA Reuss 



Plate 1, figs. 2c-c 



Ehrenbergina >ierrata Reuss, Denkschr. Akad. Wiss. Wien, vol. 1. 1850, p. 377, 

 pi. 48, figs. la-c. 



Test small, broadly ovate in front view, chambers numerous, mostly 

 rather low and broad, increasing in height in the adult, sutures on 

 the ventral side depressed, on the dorsal side flush with the surface; 

 periphery serrate, the outer edge of the chamber thin and carinate 

 with the posterior angle slightly produced ; surface smooth; aperture 

 elongate, slightly curved. 



The tjT^pes of this species are from the Miocene of Austria. 



Many authors have referred specimens to this species of Reuss, 

 but a comparison of the figures will show them to be \evy different. 



SPECIES FROM THE PLEISTOCENE 



EHRENBERGINA BICORNIS H. B. Brady 



Plate 1, figs. 5a, h 



Ehrenbergina bicornis H, B. Brady, Quart. Journ. Geol. Soc, vol. 44, 1888, p. 5, 

 pi. 1, figs. 3a, b. 



"Test subspherical, regularly biserial, earlier portion helicoid; 

 margin entire; armed with two stout spines, one at each side, directed 

 outwards." 



