172 FORAMINIFERA OF THE CRAG. 



Cassidulina laevigata, Oreene, 1871. Manual Protozoa, p. 15, fig. 3 e. 



— — Zdttel, 1876. Handb. Palseout., part 1, p. 91, fig. 29. 



— — Figuier, 1873. Ocean "World, p. 84, fig. 21. 



— — Schwager, 1877. Boll. E. Com. Geol. Ital., vol. viii, 



p. 26, pi. o, fig. 67. 



— — IficJwlson, 187 9. Manual Palseont., vol. i, p. 116, fig. 18?». 



— — Terrigi, 1880. Atti Accad. Pont. N. Lincei, vol. xxxiii, 



p. 199, pi. ii, fig. 47. 



— — ScMumberger, 1SS2. Feuille Jeun. Nat., part 1, fig. 15. 



— — Jones, 1884. In Microgr. Diet., 4th edit., p. 136, 



pi. xxiii, figs. 45 o, b. 



— — Brady, 1884. Eeport ' Challenger,' p. 428, pi. liv, figs. 



1—3. 



— — Quenstedf, 1885. Handb. Petref., 3rd edit., part 5, 



p, 1059, pi. ixxxvi, fig. 59. 



— — Basset, 18S5. Ann. Soc. Sci. Charente-Inf., p. 162, 



fig. 41. 

 — - — Brady, Parker, and Jones, 1888. Trans. Zool. Soc, 



vol. xii, part 7, p. 221, pi. xliii, 

 fig. 11. 



— — Terrigi, 1889. Mem. E. Accad. Lincei, ser. 4, vol. vi, 



p. Ill, pi. V, fig. 9. 



— — Egger, 1893. Abhandl. k. Bayer. Akad. Wiss., vol. xviii, 



part 2, pp. 276, 302, pi. vii, figs. 47, 

 48, 54—56. 



— — Goes, 1894. K. Svensk. Vet.-Akad. Handl.,vol. xxv, No. 9, 



p. 43, pi. viii, figs. 418—420. 



Characters. — Neai'ly circular, biconvex, with tbin edge, sometimes partially 

 keeled ; long, curved, very slightly inflated chambers. 



Authors seem well agreed as to the characters of the tyjjical Gassidulina Icevigata. 

 C. punctata of Reuss does not appear to present any peculiarities necessitating 

 varietal separation ; and the number and size of the pseudopodial apertures vary 

 in different individuals of almost every species of hyaline Foraminifera, and, 

 indeed, alter with the age of the shell ; and it is on these foramina rather 

 than any more important data that Prof. Reuss has depended for its diagnosis. 

 For the same reasons the G. sicula of Seguenza is included. Professor 

 Williamson was probably right in regarding G. pulchella of d'Orbiguy as a repre- 

 sentative of modifications having no morphological significance unless present to 

 a much greater degree than shown in the figures of the South-American specimen. 



Occurrence. — Gassidulina laevigata is most frequently found in the temperate, 

 arctic, and antarctic seas ; but it is not confined to those latitudes. Its 

 bathymetrical range extends from 60 to 1675 fathoms. 



Its earliest recorded appearance as a fossil is from the London Clay of the Isle 



