Foraminiferay/'o^M the Coast of Norway. 291 



appropriate trivial name ; and in regarding the other forms as 

 varieties, often worthy of some distinctive mark, number, or 

 even name. 



Figs. 1 and 2 (PI. X.) represent an elongate, somewhat arched, 

 flattened, keeled, sheath-like shell, with a produced, marginal, 

 round aperture. It is similar in all essential characters to the 

 lenticular Ci-istellaria above described, fig. TO, excepting in the 

 almost total absence of spirality. It is indeed the non-coiled 

 form of Cristellaria rotulata. Such a condition is of very fre- 

 quent occurrence wherever Cristellana is a common shell*. The 

 gradations of form from the closed-up nautiloid shell to the 

 elongate form (" Marginulina^^ of authors) are very numerous 

 in the London Clay and other Tertiariesf, in the Chalk, Gault, 

 Kimmeridge-clay, and the Lias J. 



In fig. 1 v/e may observe an instance of a small intercalary 

 chamber, — the result of injury or of a temporary stunted growth. 



The Norway dredgings afforded about twenty specimens of the 

 rotulate Cristellaria, and two of the marginuliforra specimens (all 

 from Nordland, at 160 fathoms). 



This Cristellaria is common in the recent state (but of very 

 small size) at Margate ; and still smaller at Skye § and Shet- 

 land 1|, and in Australia. This shell, of equal size with the 

 Norway specimens, but rather flatter in shape, is found fossil 

 in San Domingo; nor does it appear possible to separate it 

 (except as a conveniently distinguished variety) from the large 

 and keeled forms {Cristellaria Cassis) common in the pliocene 

 beds of Spain (Malaga), Italy, and Austria. 



The rotulate Cristellaria is common in the Tertiary deposits, 

 the Chalk, Chark-marl, Gault, and in some of the Oolites. 



15. Globigerina bulloides, D'Orb. PL XI. figs. 1 1, 12. 



Globigerina bulloides, D'Orb. Ann. des Sc. Nat. vii. p. 277. no. 1 ; Modeles, 



no. 17 & no. 7fi; Foss. For. Bass. Vieun. p. 163. pi. 9. f. 4-(). 

 Globigerina cretacea, D'Orb. Mem. Soc. Geol. Fr. iv. p. 34. pi. 3. f. 12-14. 



* An analogous companionship of the rotulate Cristellaria and a mar- 

 ginuliform variety is to be found in Prof. Bailey's " Microscopical Exami- 

 nation of Soundings made by the U. S. Coast-survey off the Atlantic Coast 

 of the U. S.," Smithsonian Contributions to Knowledge, vol. ii. 1851. 

 In this case the two forms {Robulina D'Orbignii and Marginulina Bacheii, 

 Bailey) accompany each other in the soundings of from 51 to 90 fathoms. 



t See Foss. Foram. Bass. Vienn. pi. 3 : compare f. 9-15 and f. 24, 26, 28, 

 37 ; also f. 22, 34, and 36. 



X Bornemann, Liasformat. Gottingen, pi. 4. 



§ We have to thank Prof. Williamson for numerous interesting Fora- 

 miuifera fi-ora this locality. 



II Both Prof. Williamson and Mr. Bowerbank have kindly favoured us 

 with specimens and sea-sand from Shetland. 



19* 



