'UDER II 



FORAMINIFERA 



33 



arranged in a depressed spire, subsequeiitly becoming cyclical. Lias to 

 Recent. Various subgeiiera, named by d'Orbigny Truncatulina, Anomalina, 

 Planulina, etc., are based upon slight modifications in form. 



Rotalia Lam. (Fig. 20 Ä). Test finely perforated, with segments in turbinoid 

 spire. Septa composed of two slightly separated lamellae, with anastomosing 

 canals occupying the intermediate space. Base often thickened by supplemental 

 skeleton. (?) Silurian. Upper Jura to Recent. 



PulvinuUna Parker and Jones (Fig. 20 B). 

 Rotaliform, but septa simple without being per- 

 forated by a canal System. Lower Lias to Recent. 



Endothyra Phill. (Fig. 20 C, D). Test cal- 

 careous, composed of an external coarsely per- 

 forated and an internal compact layer, the latter 

 finely granulär; segments numerous, coiled in 

 an irregulär spiral, terminal Chamber opening by 

 several apertures. Abundant in Lower Carbon- 

 iferous, and existing at the present day, ac- 

 cording to Brady. 



Calcarina d'Orb. (Fig. 21). Test discoidal, with dissimilar upper and lower 

 surfaces ; Chambers spirally coiled. Exterior encrusted with a supplemental 

 skeleton which fills up all depressions and forms spinous or spur-like processes 

 traversed by coarse canals. Upper Cretaceous to Recent ; very abundant in 

 Maestricht Chalk. 



Fig. 21. 



CalcMrina calcitrapoides Lam. Upper 

 Cretaceous (Tuffkreide) ; Maestricht, 

 Holland. 



Siibfamily C. Tinoporinae Brady. 



Test of irregularly massed Chambers, the early anes more or less distinctly spiral 

 in their arrangement, usually without a general aperture. 



Tinoporus Montf. Patellina Williamson. 



The Recent genera Carpenteria Gray, Rupertia Jones, etc., are distinguished 

 by their extremely irregulär, coarsely perforated and usually adherent tests, 

 which sometimes attain considerable size and often contain agglutinated, 

 Sandy or various other foreign particles. Thalamopora Roemer, occurring in 

 the Cretaceous, probably also belongs to this subfamily. 



Family 9, Nummulitidae. 



Test calcareous, finely tubulated, polythalamous, free, spiral, usually bilaterally 

 symmetrical. 



Subfamily A. Fusulininae Brady. 



Test fusiform or siibglobular Chambers extending from pole to pole, each convolu- 

 tion completely covering the preceding whorls. 



Schwagerina Möller. Test spherical, finely perforated. Primary and 

 secondary septa simple, thin, straight ; secondary chamberlets communicating 

 with the next following principal chamber by means of a basal aperture. 

 Abundant in Lower Carboniferous rocks of Japan, China, Sumatra, North 

 America and Russia. 



VOL. I D 



