STUDIES EST FORAMINrFERA 



163 



Globigerina senni (Beckmann) 



Plate 35, Figures lOa-12 



Sphaeroidinella senni Beckmann, Eclog. Geol. Helvetiae, vol. 

 46, No. 2, pp. 394^95, pi. 26, figs. 2-4, text-fig. 20, 1953. 



Stratigraphic range: Globorotalia palmerae zone 

 to Truncorotaloides rohri zone, Navet formation. 



Locality: Figured hypotjrpes (USNM P5705a-c) 

 from the Porticulasphaera mexicana zone, Navet forma- 

 tion ; same locality as given for Hastigerina micra (Cole) 

 (p. 161); sample Hg 8581 (TTOC 215782). 



Kemarks: Globigerina senni was originally described 

 by Beckmann as a Sphaeroidinella. Sutm-al supple- 

 mentary apertures and chamber flanges, which are 

 typical for the genus Sphaeroidinella, do not exist in 

 this species. It is therefore placed in Globigerina. 

 The species is foimd in all Navet zones except the 

 highest. It is likely that it developed from the upper 

 Lizard Springs Globigerina taroubaensis Bronnimann, 

 a species lacking the granular particles usually seen 

 surrounding the ujnbilical area in Globigerina senni. 



Globigerina linaperta Finlay 



Plate 36, Figures 5a-b 



Globigerina linaperta Finlay, Trans. Proc. Roy. See. New Zea- 

 land, vol. 69, p. 125, pi. 13, figs. 54-57, 1939.— Bronnimann, 

 Bull. Amer. Paleontol., vol. 34, No. 143, pp. 16-17, pi. 2, 

 figs. 7-9, 1952.— BoLLi, U. S. Nat. Mus. Bull. 215, p. 70, 

 pi. 15, figs. 15-17, 1957. 



Stratigraphic range: Globorotalia pseudomenardii 

 zone, Lizard Springs formation to Globigerapsis semi- 

 involuta zone, San Fernando formation. 



Localitt: Figured hypo type (USNM P5715) from 

 the Porticulasphaera mexicana zone, Navet formation; 

 Brasso-Tamana Road, near milepost 12%, Central 

 Range (see text-fig. 25) ; sample K 8814 (TTOC 177755). 



Globigerina boweri BoUi, new species 

 Plate 36, Figures la-2b 



Shape of test low trochospiral ; equatorial periphery 

 distinctly lobate (trilobate) ; axial periphery rounded. 

 Wall calcareous, perforate, surface very finely pitted. 

 Chambers spherical, early ones somewhat compressed 

 and slightly subangular; about 12, arranged in about 

 2% whorls; the Z-ZVi chambers of the last whorl increase 

 rapidly in size. Sutures on spiral side: in early stage 

 radial to sUghtly curved, in late stage radial or oblique, 

 depressed; on umbihcal side radial, depressed. Um- 

 bilicus narrow. Aperture a distinct arch, commonly 

 with a short lip or rim ; interiomarginal, umbilical, with 

 a tendency to become umbilical-extraumbilical. Coil- 

 ing predominantly dextral (90 percent or more) in the 

 Hantkenina aragonensis and Globigerapsis kugleri zone, 

 Navet formation. Largest diameter of holotype 0.4 mm. 



Stratigraphic range: Hantkenina aragonensis zone 

 to Globigerapsis kugleri zone, Navet formation. 



Locality: Holotype (USNM P5711) from the Hant- 

 kenina aragonensis zone, Navet formation; outcrop on 



left side of right branch of Nariva River, about 450 

 feet from its jimction, Central Range, Trinidad (coor- 

 dinates N:314350 links; E:487360 links) ; sample K 

 9077 (TTOC 178166). Figured paratype (USNM 

 P5712) from the Hantkenina aragonensis zone, Navet 

 formation; in small ravine between mile posts 12}^ and 

 12}^ of the Brasso-Tamana Road and the Navet River, 

 Central Range (see text fig. 25) ; sample HGK 8820 

 (TTOC 177760). 



Remarks: Globigerina boweri, new species, differs 

 from G. linaperta Finlay in having a higher arched 

 aperture which has the tendency to be slightly extra- 

 umbilical in position. Especially the earlier chambers 

 are somewhat compressed which gives them a slightly 

 subangular aspect. 



The species is named for Mr. T. H. Bower, senior 

 exploitation geologist of The Trinidad Oil Company. 



Globigerina yeguaensis Weinzierl and Applin 



Plate 35, Figures 14a-15c 



Globigerina yeguaensis Weinzierl and Applin, Journ. Paleontol., 

 vol. 3, No. 4, p. 408, pi. 43, figs, lar-b, 1929. 



Stratigraphic range: Hantkenina aragonensis zone, 

 Navet formation to Globorotalia cocoaensis zone, San 

 Fernando formation. 



Locality: Figured hypotype (USNM P5708) from 

 the type locality of Globigerapsis semiinvoluta zone, 

 Navet formation (see p. 159) ; sample Ky 7 (TTOC 

 144343) . Figured hypotype (USNM P5707) from the 

 Porticulasphaera mexicana zone, Navet formation; 

 same locality as given for Hastigerina micra (Cole) 

 (p. 161); sample Hg 8581 (TTOC 215782). 



Remarks: There is considerable variation in the 

 specimens regarded as belonging to Globigerina yeguaen- 

 sis. All forms are distinctly lobate, display a fairly 

 open umbilicus and have the apertures of the last, 

 occasionally also of earUer chambers protected by a 

 fragile lip. 



In typical forms the 3-3/^ chambers of the last whorl 

 increase rapidly in size (fig. 14a-c) ; in others with 4 

 chambers the increase is more moderate (figs. 15a-c). 

 G. venezuelana Hedberg is a more compact form than 

 G. yeguaensis. It has a less open umbilicus and shows 

 no apertural lips. G. yeguaensis has not been seen 

 with a rudimentary final chamber, a feature often 

 present in G. venezuelana. 



Globigerina cf. trilocnlaris d'Orbigny 

 Plate 36, Figures 3a-b 



Stratigraphic range: Globorotalia lehneri zone, 

 Navet formation to Catapsydrax dissimUis zone, 

 Cipero formation. 



Locality: Figured specimen (USNM P5713) from 

 the Globorotalia cocoaensis zone, San Fernando forma- 

 tion; Soldado Rock Island (see Kugler, 1938); sample 

 K3741 (TTOC 190838). 



396818—57- 



