146 THE FORAMINIFERA 



aperture an arched slit at umbilical margin of last chamber. Planor- 

 bulina, d'Orb. Normally adherent, compressed or complanate ; chambers 

 very numerous, at first on spiral, later on cyclical plan, and each chamber 

 opening at the periphery ; walls coarsely porous. Truncatulina, d'Orb. 

 Free or adherent, rotaliform, the inferior face generally more convex 

 than the superior ; aperture a curved slit, near the superior (apical) 

 margin of the last chamber. Anomalina, P. and J. Like Truncatulina, 

 but more nearly plano-spiraL Carpenteria, Gray. Adherent, spiral, 

 convex, or monticular ; chamber.? few ; aperture at apex of final segment. 

 Rupertia, Wallich. Columnar, attached by a spreading base, chambers 

 numerous, spirally arranged, aperture at the basal end of terminal suture 

 of last segment. Pulvinulina, P. and J. Rotaliform, finely porous, 

 chambers few, with lines of secondary deposit over the sutures ; aperture 

 large, at the umbilical margin of the last segment. Rotalia, Lamk. 

 Rotaliform, finely porous, with secondary deposit over sutures or in 

 umbilicus ; aperture nearer the peripheral than the umbilical margin 

 of the last chamber ; larger spp., with interseptal canals. (Fig. 50.) Cal- 

 carina, d'Orb. Rotaliform, lenticular, with radiating spines at periphery ; 

 canalicular skeleton largely developed. 



FAMILY 3. TINOPORIDAE. Test of irregularly massed chambers, the 

 early ones more or less distinctly on a spiral plan ; usually without 

 any general aperture. Genera Tinoporus, Carp. Lenticular or sub- 

 spheroidal, with radiating marginal spines, early chambers arranged in 

 a plano-spiraL Gypsina, Carter. Free and spheroidal or attached and 

 spreading, coarsely perforated, no canal-system. Aphrosina, Carter. Poly- 

 trema, Risso. Test usually pink, at first rotaliform and free, then 

 adherent, encrusting or arborescent. 



ORDER 10. Nummulitidea. 



Test calcareous, finely tubulated, free, spiral, bilaterally symmetrical 

 (except Amphistegina), the higher forms with canalicular skeleton and 

 canal system. 



FAMILY 1. FUSULINIDAE. Test fusiform or subglobular, chambers 

 extending from pole to pole, each convolution completely enclosing the 

 previous whorls. Genera Fusulina, Fischer. Chambers entire. (Fig. 

 59.) Schwagerina, Moller. Chambers subdivided. 



FAMILY 2. POLYSTOMELLIDAE. Test nautiloid. Genera Nonionina, 

 d'Orb. Canalicular skeleton rudimentary or absent, aperture a simple 

 curved slit. Polystomella, Lamk. Canalicular skeleton more or less 

 fully developed ; aperture a V-shaped line of pores. 



FAMILY 3. NUMMULITIDAE. Test lenticular or complanate ; a 

 canalicular skeleton and complex canal -system in the higher forms. 

 Genera Archaediscus, Brady. Lenticular, consisting of a non-septate 

 tube irregularly coiled, embedded in finely tubulated envelope. Amphi- 

 steyina, d'Orb. Lenticular, inequilateral, chambers spirally arranged, 

 equitant, the alar prolongations simple on one side of the test, subdivided 

 on the other. Operculina, d'Orb. Piano-spiral, the whole of the con- 

 volutions exposed ; canal-system well developed. (Fig. 55.) Nummulites, 

 Lamk. Lenticular or complanate, piano-spiral, regular, chambers equitant 



