EOEAMINIFEEA FEOM THE NOETH ATLANTIC AND AECTIC OCEANS. 
385 
Scheme of the arrangement of the chief subspecific forms of Discorbina. 
r trochicliformis, Lam., sp., Ann. Mus. viii. pi. 62. fig. 8. Eossilfrom Grignon. Coarsely perfo- 
rate, valvular or flapped, valvules marked by a mass of granules. It is an isomorpli of 
Polystomella craticulata. 
Turbo, D’Orb., sp., Modeles, No. 73. Eossil from Grignon. Coarsely perforate. Valvules 
distinct. This is the typical species. 
1. Conical. <( rosacea, D’Orb., sp., Modeles, No. 39. Eossil from Bordeaux ( [=Asterigerina Planorbis, 
D’Orb.). It is delicately perforate ; valvules distinct. 
Pileolus, D’Orb., sp., Eor. Amer. Mer. pi. 1. figs. 15-17. Erom India, Australia, &c., and fossil 
from Grignon. Small ; conical or hemispherical : chambers vertical : granulate ornament 
in radiating lines. Connecting D. rosacea with D. Parisiensis. It has its extreme flatness 
in (Bos.) semistriata, D’Orb., For. Cuba, pi. 3. figs. 15-17. 
vesicular is, Lamk. Ann. Mus. viii. pi. 62. fig. 7 ( =(Bot .) Gervillii, D’Orb. Modeles, No. 72). 
Erom Australia, and fossil at Grignon. Carpenter, Introd. Eor. pi. 13. figs. 2, 3. 
rimosa, Parker and Jones (Carpenter, Introd. Eor. p. 205). Eossil at Grignon: recent from 
India to Australia, including Fiji. Plate XIX. fig. 6. 
dimidiata, Parker and Jones (Carpenter, Introd. Eor. p. 201. fig. 32, B.). Plano-convex. 
Plate XIX. fig. 9. 
elegans, D’Orb. Modeles, No. 42. Eossilfrom Bordeaux (—(Rot.) complanata, Eor. Eoss. Yien. 
pi. 10. figs. 10—15). Passing insensibly into D. vesicularis. 
globularis, D’Orb. Modeles, No. 69 —(Hot.) semiporcita, Egger, sp. Miocene, Germany. 
obtusa, D’Orb. For. Foss. Yien. pi. 11. figs. 4-6. 
globigerinoicles, Parker and Jones. Extreme of D. vesicularis, running into T). elegans. It is 
an isomorph of Cymbalojpora bulloicles, D’Orb. (Bosalina, Cuba, pi. 3. figs. 2-5). Plate 
XIX. fig. 7. 
Binlchorsti, Eeuss, Sitz. Akad. Wien. xliv. pi. 2. fig. 3. This is an isomorph of Pulvinulina 
caracollct, Boem., sp. Limbate. 
'Parisiensis, D’Orb., sp., Modeles, No. 38. Eossil at Grignon. Ornamented with granular 
lines. 
Cora, D’Orb., sp., Eor. Amer. Me'r. pi. 6. figs. 19-21. Complanate, and round-edged ; pro- 
bably representing a somewhat starved condition. 
Berthelotiana, D’Orb., sp., Eor. Canaries, pi. 1. figs. 28-30. 
biconcava, Parker and Jones (Carpenter, Introd. Eoram. p. 201. fig. 32, G). Complanate, 
with raised square edges. Plate XIX. fig. 10. 
The oldest known are Discorbina Turbo and I). Binlchorsti, both in the Maestricht 
Chalk. 
Discorbina Turbo , Var. rosacea , D’Orbigny, sp. Plate XVI. hgs. 28 a, 28 b (North 
Atlantic). 
Discorbina rosacea , D’Orb., sp. (Modeles, No. 39), has an exquisitely sculptured, and 
more delicately porous shell than usual (the margin only may be porous) ; its astral flaps 
form sometimes a secondary system of chambers. These characters are developed largely 
in D. Turbo , D’Orb., sp., the type of the whole group, from which this flat variety has 
no essential distinction. D. rosacea is rather common and of the middle size on the 
Irish plateau at 43 fathoms. 
2. Vesicular: 
valves feeble in 
the feeble vesi- 
cular forms, 
especially in ^ 
globidaris and 
its poor rela- 
tions. 
3. Outspread 
(more or less 
complanate) : j 
valves feeble in 
the small out- 
spread forms. 
