from the " Cambridge Greensand." 311 



Cristellaria rotulata (Lara.). 



LenticaUtes rotulata, Lamarck, 1804, Annales du Museum, vol. v. 



p. 188, no. 3 ; Tableau Encycl. et Meth. pi. cccclxvi. fig. 5. 

 Cristellaria rotulata (Lam.), d'Orbigny, 1840, Mem. Soc. geol. France, 



ser. 1, vol. iv. p. 26, pi. ii. figs. 15-18; Chapman, 1896, Journ. R. 



Micr. Soc. pp. 5, 6, pi. i. figs. 8 a, b. 



This species was recorded by G. R. Vine from Cambridge. 

 It is common at S waff ham. 



Cristellaria rotulata (Lam.), var. macrodiscus, Reuss. 



Cristellaria macrodisca, Reuss, 1862, Sitzungsb. d. k. Ak. Wiss. Wien, 



vol. xlvi. p. 78, pi. ix. figs. 5 a, b. 

 Cristellaria rotulata (Lam.), var. macrodiscus, Reuss, Chapman, 1896, 



Journ. R. Micr. Soc. pp. 6, 7, pi. i. figs. 9 a, b. 



This variety is frequent at Swaffham. 



Cristellaria gaultina, Berthelin. 



Cristellaria gaultina, Berthelin, 1880, Mem. Soc. g6ol. France, ser. 3, 

 vol. i. no. 5, p. 49, pi. iii. figs. 15-19; Chapman, 1896, Journ. R. 

 Micr. Soc. pp. 7, 8, pi. i. figs. 10 a, 6, 11. 



This species ranges throughout the Gault, besides occurring 

 at several horizons above the Cenomanian. In the Cambridge 

 Greensand of Swaffham and elsewhere C. gaultina is exces- 

 sively common and attains to a great size, some specimens 

 being 3 millim. across the disk. 



Cristellaria sternalis, Berthelin. 



Cristellaria sternalis, Berthelin, 1880, Mem. Soc. geol. France, ser. 3, 

 vol. i. no. 5, p. 54, pi. iii. figs. 2 a, b; Chapman, 1896, Journ. R. 

 Micr. Soc. p. 8, pi. ii. figs. 1 a, b. 



This species does not attain to so large a size in the Cam- 

 bridge Greensand as in the Gault. It is frequent at 

 Swaffham. 



Cristellaria diademata, Berthelin. 



Cristellaria diademata, Berthelin, 1880, Mem. Soc. geol. France, s<5r. 3, 

 vol. i. no. 5, p. 51, pi. iii. figs. 4, 5, 12, & 13 ; Chapman, 1896, 

 Journ. R. Micr. Soc. p. 8, pi. ii. figs. 2 a, b. 



One fine specimen from the Greensand of Swaffham. 



