from Southern yiif't-iu. 2()5 



tlie tvpe of DiscocijcliiKi, b.-iiij:^ misintv^-rpretcd by Giimbt'l, 

 subsequent writers have deeined it necessary to introduce tlie 

 name of Orthophragmina in its place. 



The follow ino^ genera ii cognized by Scliluinbergcr (memoir 

 before quoted, 1001, pp. 463, 464) constitute the Uibitoidal 

 j,'roup of the Foraminifera as now understood: — 



(1) Oil/itvichsj Orbigny, with rhomboidal equatorial chambers 



augmenteil sensibly in hnight towards the circum- 

 ference, where they are frcquetitly subdivided ; perfo- 

 rations of tlie septa rather strong. 



Ty y)e= Orbital ites media, Aichiac. 



Fcnucrion (Did Localities. Upper Cretaceous (Dor- 

 donien) of i^'ranc?; &c. 



(2) Orthophragmina, Muuier-Chalmas, with equatorial cham- 



bers " [)ar;(llt'lipedi(|ues," = square or rectangular. 



Tvpe= Orbito/ifes pmtti, Michelin. 



Foriwition and Localities. Eocene to Oligocene 

 (Priabonian), Biarritz, North Italy, Kressenberg, &c. 



(3) I^f'pidocycUna, Giimbel, with rounded or hexagonal 



equatorial chambers, and with finely perforated septa. 



'\'y\)Q.=^Nummnlitcs mantelli, Morton. 



Formation and Localities. Oligocene (Vicksburg 

 Group), N. America, and Miocene of Europe. 



(4) Mgogypsina, Sacco, with spiial embryo more or less 



excentiic and lanceolate equatorial chambers. 



'Vy[)(i = jS'ummulites irregularis, Michelotti. 



Formation and Luoalinea. ]\liocene (Aquitaniaii), 

 Italy, &Q. 



The main organisms of this limestone and those only that 

 can be seen in a general way without microscopical aid are of 

 abundant occurrence, being Irequently closely packed together 

 in layers, and resembling in this mariner some rocks from 

 Biarritz and Kressenberg containing Orthophragmina praiti 

 [ = pajigracea of Gumbel, non Boubee) of Eocene age. 



Tlie specimens also agree in being of nearly the same 

 diameter, probably rather smaller, and also in their excessive 

 thinness — so much so, that horizontal intennil views are 

 ditiicult to obtain. 



Some excellent sections have, however, been mad?, by 

 Mr. Richaid Hall, the Senior Formatore of the Britisli 

 Museum (Natural History), which exhibit chiefly vertical 



