218 NTMPHACEA. 



the amount of 24, have been figured in parts 14 to 16, of the 

 above mentioned work. Eecent Nuculse are found from the 

 frozen to the torrid zones, and the fossil species occur in nearly 

 all the beds from the Pliocene to the Carboniferous system. 

 PL vii. fig. 137. 



NUMMULACEA. Bl. The third family of CeUulacea, Bl. 

 described as containing shells or calcareous bodies, which are 

 characterized as discoidal, lenticular ; without the slightest 

 traces of whorls to be seen externally. The whorls are nume- 

 rous, internal, and divided into a great number of cells, which 

 are separated from each other by imperforate septa. This family 

 contains the genera Nummulites, Siderolites, Yorticialis, HeH- 

 cites, Orbiculina, Placentula. 



NTJMMULITES. Lam. {Nummus, money.) Fam. ISTautilacea 

 Lam. — Bescr. Orbicular, convolute, shevnng no trace of spire 

 externally ; interior divided into cells spirally arranged. — Obs. 

 The singular fossils composing this genus receive their name 

 from their external resemblance to a battered coin. JS". lenti- 

 culina. PI. xxii. fig. 472, 473. 



NUX. Humph. Cxclas, Lam. 



NTMPHACEA. Lam. A family belonging to the order Con- 

 chifera Dimyaria, Lam. Ligament external, placed on a pro- 

 minent fulcrum. This family contains the following genera : 



1. SANGHJiiiroLAEiA. E-ostrated, gaping ; two cardinal teeth 



in each valve, including Soletellina and Lobaria. Eig. 

 98, 99. 



2. PsAMMOBiA. Quadrate ; valves closed, including Psam- 



motsea. Eig. 100. 



3. CoKBis. Thick, fimbriated; a cardinal tooth in the centre 



of a pit. Eig. 101. 



4. GrRATELOUPiA. A series of small teeth filling a triangular 



area. Eig. 102. 



5. EaERiA. One singleand one double cardinal tooth. Eig. 103. 



6. LirciNA. Bounded; anterior muscular impression tongue- 



shaped. Eig. 104. 



