Foratninifera/ro//i the Coast uf Norway. 289 



large convex umbilici ; and sometimes thin, and either margined 

 with a sharp jagged edge and prickles, or unkeeled and rounded 

 at the edge. The fenestration of the surface appears to be a 

 better specific guide than the shape, size, or spinosity of the 

 shell, or even than its comparative solidity or tenuity. The 

 habitat of individuals, according to depth of water and its estua- 

 rine or marine conditions, is well indicated by the relative con- 

 vexity, strength, and coarseness of their shells. The estuarine 

 variety is generally extremely thin- walled, round-edged, and 

 keelless. 



14. Cristellaria Calcar, Linn. sp. PL X. figs. 10-12, and 

 figs. 1 & 2 (var.). 



Nautilus Calcar*, Linn. Syst. Nat. 12 ed. p. 1162; Gmel. p. 3.j70. 

 Nautilus Calcar, varr. a, /3, y, S, f, {"> '?. ^, ^, k, ^, M, Fichtel & Moll, Tes- 



tacea Microscopica, &c., pp. 69, &c- pi. 11, 12, 13. 

 Nautilus papillosus, Fichtel & Moll, ih. pi. 14. figs, a, ti, c. 

 Robulus cultratus, Montfort, Conchyl. p. 214. 

 Robulina cultrata t, D'Orb. Ann. Sc. N. vii. p. 287, no. 1 [Field, varr. ^, 



Robulina Calcar, D'Orb. Ann. Sc. N. vii. p. 289. no. 12 (Ficht. varr.y,S,t). 

 Robulina costata, D'Orb. Ann, Sc. N. vii. p. 289. no. 13 (Ficht. var. e). 

 Robulina aculeata, D'Orb. Ann. Sc. N. vii. p. 289. no. 14 [Ficfit. varr. a, 6, 



Robulina cultrata, D'Orb. For. Foss. Bass. Vienn. p. 96. pi. 4. f. 10-13. 

 Lenticulites rotulata, Lamarck, Anual. Mus. v. p. 188. pi. 62. f. 11. 

 Nummulina rotulata, D'Orb. loc. cit. p. 296. no. 8. 

 Cristellaria rotulataX, D'Orb. Mem. Soc. Ge'ol. Fr. iv. p. 26. pi. 2. f. 15-18. 



Shell hyaline, lens-shaped, spiral, involute, nautiloid ; chambers 

 slowly increasing in size, varying from about four to ten in the 

 outer whorl, subtriangular in side-view, their inner or umbilical 

 angular portions overlapping the two surfaces of the former 

 whorl; sutures sometimes slightly sunken, sometimes marked 

 by variable linear costse, either partial, entire, or granular, and 



* Linnaeus included, and not without reason, the compressed form of 

 Cristellaria (LedermuUer, Micr. pi. 8. fig. d), now known as C. Cassis, 

 under this appellation. C. Cassis is not specifically separable from the 

 thicker and more regularly circidar C. Calcar ; but, for the sake of a useful, 

 though artificial, distinction, we here refer to the synonyms of C. Calcar 

 (proper) only. 



t To the uvnnerous synonyms recognized by D'Orbigny for this species, 

 and enumerated in the "Tableau des Cephalopodes" here quoted, must 

 be added many more fi-om his subsequent list of " species" both of " Ro- 

 bulina" and " Cristellaria." Very numerous varieties of this shell have 

 been figiu-ed and named by authors ; for example, the series of Robulina 

 and Cristellaria; in the Zeitschrift deutsch. geol. Gesell. vol. iii. pi. 4, and 

 vol. vii. pi. 13-15; and nearly all the Robulince, and several of the Cristel- 

 laria, in the Foram. Foss. Bass. Vienn. (pi. 4. f. 1-7, 10-27; pi. 5. f. 1-4). 



X See D'Orb. loc. cit., and Morris's Catal. Brit. Foss. 2nd edit. p. 33, for 

 further svnouvms. 



Ann.' Sf Ma(/.N. Hist. Ser. 2. Vol.x'w. 19 



