OKI'KK I 



FORAMIXIKKK'A 



Nubecularidae. Bnuly. 



attached, extreme!// ///>'>////"/ in rnnti,n,\ 

 Triassic to Recent. 



Kaniily 1. 



Test comparatively A//v//--.s-/':r/, 

 with one or with several general apertures. 



The recent genus Nubecnlaria, Dfr., belonging to this family occurs fossil' 

 in ;ill formations from the Triassic onward, and is particularly abundant in 

 the Miocene (S;irm;iti;ui stage) of Bessarabia, Russia. 



Family 2. Peneroplidae. Schwager. 



Test piano-spiral or cyclical, bilateral!// x//n/ metrical, usually polythalamous, more 

 rarely monothalamous. Triassic to Recent. 



Cornuspira, Schultze (Fig. 19). Test composed of numerous piano-spiral 

 convolutions ; oral aperture simple, terminal ; monothalamous. Lias to 

 Recent. 



Peneroplis, Montf. (Fig. 20). Test discoidal, complanate, polythalamous ; 

 direction of growth primarily spiral, gradually becoming rectilinear, while 



FIG. ly 



FIG. 22. 





Cornuspira pol // 



&yra, Reuss. Peneroplis planatus, " Orliodt na luimmis A, Orbitolites compl<m<tt", Lam. Eocene 



ligocene : Hun- Montfort. Recent; malls, d'Orb. Plio- (Calcaire Grossier): Paris. B, Portion of 



gary. Mediterranean. cene ; Sienna, Italy. same enlarged. 



rapidly increasing in breadth. Septa perforated by numerous foramina. 

 Tertiary to Recent. 



Orbiculina, Lam. (Fig. 21). Test discoidal; segments spiral at commence- 

 ment, later becoming annular ; polythalamous, septation regular, chambers 

 subdivided ; septa and walls of segments perforate. Tertiary to Recent. 



Orbitolites, Lam. (Fig. 22). Test discoidal, circular in contour, both sides 

 slightly concave in the centre, of comparatively large dimensions, and com- 

 posed of segments which 

 are disposed concentrically 

 about a few spirally wound 

 primordial chambers. 

 Polythalamous; septa 

 radially disposed, and per- 

 forated by symmetrically 



v , -i , j f . T 17 ' Alveoli na Bosci, d'Orb. Eocene (Calcaire Grossier) ; Paris. .4, Frontal 



distributed lOramma. In aspect. B, Test laid open so as to show conformation of interior; 



the more complicated c 



forms the principal segments are covered over on both sides by a thin, super- 

 ficial, multilocular layer, the chambers of which are likewise arranged in con- 

 centric rings, and communicate with the principal chambers by means of pores. 

 Lias (0. praecursor and 0. circumvulva, Giimb.), Cretaceous (0. maci'jn-<i, 



FIG. 23. 



