Foraminifera. 133 



Various modes of classification have been proposed for the OALLEBT 

 Foraminifera : the following was brought forward by tlie late ^ 

 Conrad Sch wager, and has been adopted by Zittel : — ^T^ili*'* 



Suborder I. Chitinosa. Family Gromidae. The test is chitinoufc else 16.' 

 and not known as fossil. 



Suborder II. Agglutinantia. Test composed of sand-grains or 

 other siliceous bodies agglutinated together by a compact siliceous or 

 calcareous cement. Fam. 1. Astrorhizidas ; typical genus, Saccani- 

 mina, Sars. Fam. 2. Lituolidae ; typ. gen., Lituola, Lam., Placo- 

 psilina, D'Orb. Fam. 3. Orbitolinidee ; typ. gen., Orbttolma, Lam. 



Suborder III. Poucellanea. Test of carbonate of lime, por- 

 cellaneous. Fam. 1. Nubecularidae ; typ. gen., Nuhecularia, Defr. 

 Fam. 2. Peneroplidae ; typ. gen, Peneroplis, Montf., Orhitolites, 

 Ijdim., Ah eolina,^o^(i. Fam. 3. Miliolidae ; typ. gen., Miltola, Seh. 



Suborder IV. Viteo-Calcahea. Test of glassy-porous carbonate 

 of lime, rarely arenaceous, or arenaceous with a glassy-porous 

 substratum, perforated by fine canals for the emission of the 

 pseudopodia. Fam. 1. Lagenidae ; typ. gen., Lagena,Walk., Nodo- 

 saria, Lam., Detitalina, D'Orb., Frondzcularia, Defr. Fam. 2. 

 Textularidae ; typ. gen., Textularia, Defr., Climacammina, Brady. 

 Fam. 3. Globigerinidae ; typ. gen., GUbigerina, D'Orb. Fam. 4. 

 llotalidae ; typ. gen., Rotalia, Lam., Biscorhina, Park., Endothjra^ 

 Phill., Calcarina, D'Orb. Fam. 5. Fusulinidae ; typ. gen., Fusulina, 

 Fisch. Fam. 6. Nummulinidae ; typ. gen., Nummulites, D'Orb , 

 Amphistegina, WOih, Poly stomella, D'Orb., and Orhitoides, D'Orb. 



With the Foraminifera were formerly included Eo%oon, Dactg- Wall- 

 lopora, and Receptaculites ; but the first-named is now generally «»«« ^' 

 considered to be inorganic, the second has been shown to be 

 a calcareous alga, and the last is probably a sponge. (See p. 121.) 



Foraminifera are of considerable geological importance. They 

 are represented in most of the calcareous rocks from the Ordovician 

 age to the present; but their remains are of somewhat rare 

 occurrence in the Ordovician, Silurian, and Devonian formations. 

 In the Carboniferous Limestone they are very abundant, and 

 certain limestones are mainly composed of the remains of FusuUna, 

 Saecammtna, and Fndothyra, and these genera are accompanied 

 by Nodosaria, Dentalina, and representatives of the TextularidjB, 

 llotalidae, and also the Nummulitidae. 



The calcareous marls and shales of the Lias and Jurassic 

 strata contain immense numbers, mostly of the small perforate 



