262 REPORT OF NATIONAL MUSEUM, 1897. 



Test dimorphous, etc.— Continued. 



Early chambers milioline, subsequently planospiral with more than two seg- 

 ments in each convolution Genus Hanerina. 



Chambers equi'tant, arranged as in Hanerina, the last convolution covering the 



previous whorls Genus Planispirina. 



Test planospiral or cyclical, sometimes crozier-shaped, bilaterally symmetrical : 



Subfamily Pexeropi/idin.e. 



Chamber one, an undivided planospiral tube Genus Cornuspira. 



Chambers numerous, undivided, planospiral or spiral at first and rectilinear or 



cyclical afterwards Genus Peneroplis. 



Chambers subdivided transversely; early segments embracing; arrangement 



wholly planospiral or partly cyclical Genus Orbiculina. 



Chambers subdivided into chamberlets; test discoidal Genus Orbitolites. 



Test spiral, elongated in the line of the axis of convolution.. Subfamily Alveolixix.e. 



Subglobular, elliptical, or fusiform Genus Alveolina. 



Test spherical ; chambers in concentric layers Subfamily Keramospii.erix.e. 



Chambers very numerous, irregularly shaped Genus Keramospha ra. 



Family VI. La(;enio.e. 



Test monothalanions Subfamily Lagexid.e. 



A single undivided chamber Genus Lagena. 



Test polytlialamons, straight, arcuate or planospiral Subfamily Nodosarin.e. 



Monomorphous. 



Straight or curved, circular in transverse section ; aperture central : 



Genus Nodoaaria. 

 Straight, compressed; aperture typically a narrow fissure. .Genus Lingulina. 

 Compressed or complanate; segments V-shaped, equitant: 



Genus Frondicularia. 

 Straight or slightly curved, triangular or quadrangular in sectiou : 



Genus Ekabdogonium. 

 Elongate, curved, circular in section ; aperture marginal: 



Genus Marginulina. 

 Elongate, compressed or complanate; septation oblique: aperture marginal: 



Genus Vaginulina, 

 Vaginuline; septation very oblique; aperture a long slit down the ventral 



face of the final segment Geuus Ilium I'm a. 



Planospiral in part or entirely; complanate, lenticular, crozier-shaped or 



ensiform Genus Cristellaria. 



Dimorphous. 



Early segments Cristellarian, later ones Nodosarian . .Genus Amphycoryne. 



Early chambers Cristellarian, later ones Linguline Genus Lingulinopsis. 



Early chambers ( 'risieUarian, later ones Frondicularian Genus Fl-dbellvna. 



Early chambers Frondicularian, later ones Nodosarian : 



Genus Amphimorphina. 



Early chambers Ehdbdogonian , later ones Nodosarian Genus Dentalinopsis. 



Test polythalamous; segments arranged spirally around the long axis: rarely 



biserial and alternate Subfamily Polymorphixin/E. 



Monomorphous. 



Segments bi- or tri-serial or irregularly spiral; aperture radiate: 



Genus PolymorpMna. 

 Segments arranged spirally around the long axis of the shell (rarely bise- 

 rial); aperture simple, usually surrounded by a phialine lip: 



Genus Urigerina. 

 Dimorphous. 



Early segments Polymorphine, later ones Nodosarian Genus Dimorphina. 



Early segments Uvigei-ine, later ones Nodosarian Genus Sagrina. 



