266 FORAMINIFERA 



II. Test consisting of numerous chambers, usually but two in each whorl. 



A. Periphery acute, chambers with internal incomplete septae. 



Patellina. 



B. Periphery rounded, chambers without internal septae. Patellinella. 



III. Test of numerous chambers, several in a whorl. 



A. Umbilicus usually open, not filled. 



1. Ventral side with a prolongation of the chamber over or to- 



ward the umbilicus. 



a. Test typically planoconvex, umbilicus deep. 



( 1 ) . Ventral side smooth and polished Lamarckina. 



(2). Ventral side with chambers projecting to the um- 

 bilicus Discorbis. 



b. Test strongly biconvex Valvulineria. 



2. Ventral side without prolongations across the umbilicus. 



a. Test in a low spire Gyroidina. 



b. Test in a high spire Rotaliatina. 



B. Umbilicus usually filled, not open. 



1. With a distinct umbilical plug :Rotalia. 



2. Without a- distinct umbilical plug. 



a. Apertural face with a distinct thin plate. 

 (1). Aperture simple. 



(a). Test not involute on the dorsal side.. .Cancris. 

 (b). Test strongly involute on the dorsal side. 



Baggina. 

 (2) . Aperture cribrate Neocribrella. 



b. Apertural face without a thin plate. 



(1). Aperture simple, without a neck and without a sup- 

 plementary aperture near the periphei'y. Eponides. 

 (2). Aperture with a neck and lip. 



(a) . Test globular Siphoninoides. 



(b). Test biconvex, close coiled Siphonina. 



(c). Test biconvex, uncoiling in the adult. 



Siphoninella. 

 (3). Test with supplementary apertures near the periph- 

 ery without a neck Epistomina. 



(4). Test with supplementary apertures on the dorsal 



side. .• Epistomella. 



(5). Test in the adult greatly spreading and irregular. 



Piano pulvinulina. 



Subfamily 1. Spirillininae 



Test simple, consisting of a proloculum, and a planispiral, 

 undivided, tubular second chamber, open end of the tubular 

 chamber serving as the aperture. 



