A NEW GENUS OF EOCENE FORAMINIFERA 



By Joseph A. Cushman 

 Of Sharon, Massachusetts 



In the American Tertiary there are numerous foraminifera repre- 

 senting several species which it is difficult to assign to any existing 

 genus. The nearest species to these is that described by Hantken 

 as Siderolina hochi Hantken.^ A figure of this is given here. The 

 American species are all different from this. 



The genus Siderolina was erected by Def ranee- and is the same 

 as Siderolites Lamarck ^ the type species being S. calcitrapoides 

 Lamarck. This has been at various times assigned to Siderolina 

 Defrance of which it is the type and to Galcarina d'Orbigny. The 

 model of d'Orbigny of Siderolina is of S. laevigata d'Orbigny and 

 may probably be referred to Siderolites. That genus has the young 

 rotaliform and later vesicular chambers cover the early chambers. 

 These Eocene species referred to here are planospiral, consisting of 

 but a few chambers usually each with a distinct spine and while 

 they should probably be referred to the Rotaliidae are very different 

 from Siderolites or Galcarina. The following genus is proposed for 

 them : 



HANTKENIA, new genus 



Description. — Test free, planospiral, consisting of about three 

 coils, chambers few, usually about five in the adult coil, laterally 

 compressed, wall finely or coarsely perforate, sutures distinct and 

 depressed, each chamber at least in the adult with a stout peripheral 

 spine with a hollow center, aperture tripartite one arm running 

 along either side of the base of the chamber, the other extending 

 peripherally in the apertural face of the chamber. 



Type species. — Hantkenina alabamensis, new species, from the 

 Zeuglodon bed at Cocoa post office, Alabama. 



lA magy. kir. fOldt. int. gvkonyve, vol. 4, 1875 (1876), p. 68, pi. 16, fig. 1 and Mitth. 

 Jahrb. ung. geol. Anstalt vol. 4, 1875 (1881), p. 79, pi. 16, fig. 1. 

 ='Dict. Sd. Nat, vol. 32, 1824, p. 180. 

 3 Syst. Anim. sans Vert., 1801, p. 376. 



No. 2567.-PROCEEDINGS U. S. NATIONAL MUSEUM, VOL. 66, ART. 30. 

 9122—24 1 



