FAMILY 22. LAGENIDAE 187 



Test planispiral, bilaterally symmetrical, very much 

 compressed laterally, the sides nearly parallel; aperture at the 

 peripheral angle, radiate, sometimes with the ventral slit 

 expanded, 



Jurassic to Recent. 



Genus MARGINULINA d'Orbigny, 1826 



Plate 24, figures 9, 10; plate 25, fig-ure 5 

 Genotype, by designation, Marginulina glabra d'Orbigny 

 Marginulina d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 258. 



Test subcylindrical, very early portion close coiled, later 

 uncoiled, final chambers often inflated ; aperture in the early 

 coiled portion as in Lenticulina, in the uncoiled portion becoming 

 central and terminal. 



Cambrian ( ?) to Recent. 



Genus DENTALINA d'Orbigny, 1826 

 Plate 24, figures 11, 12; plate 25, figure 6 



Genotype, by designation, Nodosaria (Dentalina) ohliqua d'Orbigny 

 Dentalina d'Orbigny, Ann, Sci. Nat,, vol, 7, 1826, p, 254. 



Test arcuate, elongate, of numerous chambers in a linear 

 series; sutures usually oblique, at least in the early portion; 

 aperture radiate, at least in the early stages, at or near the 

 periphery but becoming more nearly central in the last 

 chambers, 



Jurassic to Recent. 



Genus NODOSARIA Lamarck, 1812 



Plate 24, figure 13; plate 25, figure 7 

 Genotype, by designation. Nautilus 7'aphanistruni Linne 

 Nodosaria LAMARCK, Extract Cours Zool., 1812, p. 121, 



Test with the chambers in a straight linear series, the cham- 

 bers distinct, not strongly embracing ; sutures normally at right 

 angles to the axis; wall calcareous, finely perforate, glassy; 

 aperture central and terminal, radiate, often with a chamberlet 

 below with a rounded opening into the main cavity of the 

 chamber, 



Cambrian (?) to Recent. 



