CARBONITE ROUS AGE. H 



CARBONIFEEOUS AGE. 



(CARBONIFEROUS PERIOD.) 



PROTOZOA. 



Class RHIZOPODA. 

 Order FoFaifiiiiiifera. 



Family OAMERINID^. 



Shell comparatively large and dense, discoid, lenticular, fusiform, cylin- 

 drical, oval, or subglobose in outline ; symmetrically involute, or rarely 

 somewhat obliquely spiral. Last volution generally embracing all the 

 others, so as to present, in the typical genera, the form of an Ammonite or 

 Naiitihis. Septa nearly always double, each chamber having its own 

 walls, which, without exception, differ from the rest of the shell in being 

 destitute of the ordinary tubular structure, so that the chambers are only 

 connected by the principal aperture, and a few large " orbuline" pores. 

 Canal system radiating between the double walls of the septa, generally 

 well developed and connected with the "intermediate skeleton," secreted 

 apparently for the consolidation of the entire structure. Aperture in the 

 typical forms a narrow fissure placed symmetrically between the outer 

 wall of the j)enultimate whorl, and the inner side of the last or outer 

 series of chambers ; sometimes partly closed by a shelly secretion so as 

 to leave only a series of pore-like openings ; in AmpMstegina placed on 

 the under side of the spiral plane. 



In Dr. Carpenter's beautiful and elaborate Memoir on the Foraminifera^ pub- 

 lished by the Ray Society, in 1862, the genera included in this family (there called 

 Nummulinida) are the following, — in part, however, under other generic names, 

 viz. : Camerina, = (NummuUtes, Lamk.) AmpMstegina, Operculma, Elpliidium, = 

 {Polystomella, Lamk.) Heterostegina, Cycloclypeus, Orhitoides and Fusulina. It in- 

 cludes the largest and most highly developed of the Foraminifera, as well as those 

 possessing the most densely constructed shells. The living examples are mainly 

 confined to the tropical and temperate seas, the larger types occurring in the tropics. 



In regard to some of the names here adopted, a word of explanation may not 

 be out of place. First it will be observed we use Bruguiere's name Camerina 



^ To whicli we are mainly indebted for the characters given in the abore description. 



