STUDIES IN FORAMINIFERA 



31 



is similar in early planispiral development but has only 

 a single pair of "biserial" chambers, which are opposing, 

 however, rather than alternating, and each of which has 

 a distinct apertm-e. It differs from Cassidulina d'Or- 

 bigny in having a perforate radial wall structure rather 

 than granular and in having an early planispiral stage. 



Types and occurrence: Figured topotype (USNM 

 P3389) and unfigured topotypes (USNM P3056) from 

 the Middle Ohgocene, Boudky near Yelk6 NSmcice, 

 Moravia, Czechoslovakia. Collected by Dr. Vladimir 

 Pokorn^^. 



Kange: Oligocene to Miocene. 



Family Orbulinidae Schultze, 1854 



Type genus: Orhvlina d'Orbigny, 1839. 



Test trochospirally or streptospnally coiled or globu- 

 lar; chambers spherical, ovate or clavate; wall cal- 

 careous, perforate, radial in structure; primary apertm^e 

 mnbilical or spLroumbilical, may have secondary sutiu-al 

 or areal apertures and may have bullae and accessory 

 infralaminal apertures. 



Subfamily Globigerininae Carpenter, 1862 



Type genus: Globigerina d'Orbigny, 1826. 



CoiHng of test trochospiral to streptospiral ; chambers 

 spherical, ovate or clavate; primary aperture mnbilical 

 or spiroumbilical, may have secondary sutural aper- 

 tures. 



Range: Cretaceous to Recent. 



Genus Globigerina d'Orbigny, 1826 



Plate 4, Figures la-c 



Globigerina d'Orbigny, Ann. Sci. Nat., ser. 1, vol. 7, p. 277, 

 1826. 



Type species: Globigerina buUoides d'Ovhigny, 1826. 

 Fixed by subsequent designation of Parker, Jones and 

 Brady (1865, p. 36). 



Test free, trochospiral, chambers spherical to ovate; 

 sutures depressed, radial; wall calcareous, perforate, 

 radial in structiu-e, surface may be smooth, pitted, can- 

 cellated, hispid or spinose; aperture interiomarginal, 

 imibilical, with a tendency in some species to extend to 

 a shghtly extraumbilical position, and previous aper- 

 tures remaining open into the umbilicus. 



Remarks: Formerly considered a more inclusive 

 genus, Globigerina is now restricted to include only those 

 trochospiral species with a single large open umbilical 

 aperture. 



In Globigerina the aperture is interiomarginal and 

 primarily umbilical, leading from each chamber into 

 the open umbilicus, and the chambers are always globu- 

 lar to subglobular. Globorotalia has an interiomarginal, 

 extraumbilical-umbilical aperture, and the chambers 

 vary from ovate or subhemispherical to strongly com- 

 pressed or angular, commonly have a peripheral keel 

 but rarely are truly spherical. Praeglobotruncana has 

 an extraumbilical-umbUical aperture like that of Globo- 



rotalia, but commonly with spherical or only slightly 

 compressed chambers. 



All classifications are somewhat artificial and there 

 are some species with globular chambers whose aper- 

 tiu-al position is transitional, so that in some instances 

 it may be somewhat difficult to decide whether such a 

 species should be placed in Globigerina or Globorotalia. 



Types and occurrence: This genus, like the major- 

 ity of planktonic forms, has a wide geographic occur- 

 rence. The hypotype of G. bulloides d'Orbigny here 

 figured (USNM P3917) is from Recent beach sand at 

 Marina di Ravenna (Porto Corsini), Italy. Collected 

 by H. T. and A. R. LoeWich, Jr., March 15, 1954. The 

 original type locality of d'Orbigny was at Rimini, ap- 

 proximately 60 kilometers farther south on the Italian 

 coast. 



Range: Cretaceous to Recent. 



There is a continuous geologic record of Globigerina 

 from the Paleocene to Recent and, in addition, species 

 are found from the Hauterivian to Cenomanian in the 

 Lower and Middle Cretaceous which appear to be 

 morphologically identical. The gap in the geologic 

 record from the Cenomanian to Paleocene strongly sug- 

 gests that this genus as here recognized is polyphyletic, 

 and the Tertiary species are not direct descendants from 

 those of the Lower Cretaceous. The absence of any 

 distinguishing morphologic characters prevents their 

 separation, with the material and methods thus far 

 available, into two nominal genera. 



Genus Globoquadrina Finlay, 1947 



Plate 5, Figures 4af-6 



Globoquadrina Finlay, New Zealand Journ. Sci. Tech., vol. 

 28, No. 5 (sec. B), p. 290, 1947. 



Type species: Globorotalia dehiscens Chapman, Parr 

 and Colhns, 1934. Fixed by original designation. 



Test free, trochosph-al, umbilicate, periphery rounded 

 to truncate; chambers spherical to subangular truncate; 

 wall calcareous, perforate, radial in structure, surface 

 pitted to hispid; aperture interiomarginal, umbilical, 

 covered above by an apertural flap which may vary from 

 a narrow rim to an elongate toothlike projection, and in 

 openly umbilicate forms earlier apertures remain open 

 into the umbdicus. 



Remarks: Globoquadrina differs from Globigerina 

 d'Orbigny in having apertural flaps covering each aper- 

 ture. It differs from Globorotalia in the aperture being 

 umbilical instead of extraumbilical-umbilical in position. 



Types AND occurrence: Figured hypotype (USNM 

 P3926) and unfigured hypotype (USNM P3927) of Glo- 

 boquadrina dehiscens (Chapman, Parr, and Collins) from 

 the Miocene (Balcombian) at Balcombe Bay, Victoria, 

 Australia. CoUccted by A. C. Collins. 



Unfigured hypotypes (Cushman Coll. 14240) from 

 the Balcombian at Grices Creek, Victoria, Australia; 

 (Cushman Coll. 24844) from the Miocene at Western 

 Beach, Geelong, Victoria, Australia; and (Cushman 

 Coll. 24837) from the Lower Miocene, lower beds, 



