264 REPORT OF NATIONAL MUSEUM, 1897. 



Test consisting of irregularly heaped chambers Subfamily TIXOPORIN^E. 



Lenticular or subsph;eroidal, with radiating marginal spines and tuberculated 

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



Genus Tinopornx. 



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

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



no general aperture Genus (li/psina. 



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



apertures numerous, marginal Genus Aplirosiua. 



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

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



Genus Tlialamopora. 



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

 white Genus Polytrema. 



Family X. NUMMULINID.E. 



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

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



Fusiform or subglobular; chambers entire Geuns Fusnlina. 



Subglobular, elongated or subcylindrical; chambers subdivided by secondary 



septa Genus Scliwagerina. 



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 Subfamity NFMMULITIN/E. 



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



substance Genus Archa'discus. 



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



into two portions below Genus Amphisteylna. 



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



Genus Operculina. 

 Complanate and plauospiral; chambers divided into chamberlets: 



Genus Heterosteyina. 

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



or quite enclosing all the previous ones Genus Nnmmulites. 



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



exposing the outlines of previous convolutions Genus AssiUna, 



Complanate with thickened center, or lenticular Subfamily CYCLOCLYPEINVE. 



Composed of a single layer of chambers arranged in concentric annuli, 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 IT. ASTEOEHIZTD^B. 



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. 



