264 REPORT OF NATIONAL MUSEUM, 1897. 



Test consisting of irregularly heaped chambers Subfamily Tixoporix 1: 



Lenticular <>r subsphseroidal, with radiating marginal spines and tuberculated 

 surface; chambers arranged in tiers on each side of a central planospiral disk: 



Genus Tinopovus. 



Sphseroidal or spreading, without spines; free or adherent, structure acervuline, 



radiating or laminated; chambers rounded or polyhedral, coarsely perforated; 



no general aperture Genus Gypsina. 



Planoconvex, spreading, adherent; chambers acervuline; wall finely perforated ; 



apertures numerous, marginal Genus Aphrosiiia. 



Columnar, branching, attached by the base; segments numerous, crowded 

 around the long axis; coarsely perforated; no general aperture: 



Genus Thalamopora. 



Encrusting or branching, parasitic; surface areolated; color pink or sometimes 



white Genus Polylrema. 



Family X. Numviulinidk. 



Bilaterally symmetrical; chambers extending from end to end and arranged in con- 

 volutions perpendicular to the long axis of the shell.. Subfamily Ftsulinin/E. 



Fusiform or subglobular; chambers entire Genus Fusulina. 



Subglobular, elongated or subcylindrical; chain hers subdivided by secondary 



septa Genus Schwagerina. 



Bilaterally symmetrical, nautiloid Subfamily Polystomellin.e. 



Supplemental skeleton absent or rudimentary; no external septal pores or 



bridges; aperture a curved slit Genus Nonionina. 



Supplementary skeleton, septal bridges and canal system present; aperture a 

 V-shaped line of perforations at the base of the septal face.. Genus Polystomella. 



Lenticular or complanate Subfamily NUMMULiTiNiE. 



Lenticular, consisting of a coiled nonseptate tube embedded in a mass of shell 



substance Genus Archaidiscus. 



Lenticular, spiral, inequilateral; chambers equitant, simple above, constricted 



into two portions below Genus Amphistegina. 



Complanate and planospiral, all the convolutions visible; chambers undivided: 



Genus Operculum. 

 Complanate and planospiral; chambers divided into chamberlets: 



Genus Heterostegina. 

 Lenticular, planospiral, equilateral; chambers equitant, each convolution nearly 



or quite enclosing all the previous ones Genus Nummular*. 



Complanate, regular, equitant, but the alar prolongations thin and transparent, 



exposing the outlines of previous convolutions Genus Assilina, 



Complanate with thickened center, or lenticular Subfamily CYCLOCLYPEIN i ■:. 



Composed of a single layer of chambers arranged in concentric anuuli, with 

 superimposed laminae of finely tubulated shell substance thickest at the center : 



Genus Cycloclypeus. 



Composed of a single layer of concentric chambers, with superimposed layers of 



flattened chamberlets Genus Orbitoides. 



CATALOGUE. 



Family II. ASTEORHIZTD.K. 



Test invariably composite, usually of large size and monothalamous ; 

 often branched or radiate, sometimes segmented by constriction of the 

 walls, but seldom or never truly septate; polythalamous forms never 

 symmetrical. 



