STtJDIES IN FORAMINIFEKA 



183 



the early whorls standing somewhat above the general 

 level of the surface on the spiral side. The somewhat 

 smaller, smooth and thin-walled final chamber is also a 

 characteristic feature. 



According to Bolli (1957, p. 70) this species is re- 

 stricted to the Oloborotalia uncinata zone of the Lower 

 Lizard Springs (lower Paleocene). In the Gulf and 

 Atlantic coast Paleocene it occurs somewhat higher in 

 the section in the uppermost Paleocene, and no similar 

 forms occur in lower Paleocene samples. It occurs in 

 the Salt Moimtain limestone, Aquia, Hornerstown and 

 Vincentown formations. 



Types a nd occurrence: Figured hypotypes (USNM 

 P5121a-e) from the Vincentown formation, along north 

 bluff of Rancocas Creek, 0.3 to 0.5 mile northwest of 

 Vincentown, Burlington County, New Jersey. Collected 

 by A. R. Loeblich, Jr., and Norman Sohl. 



Figured hypotype (USNM P5122) from the Salt 

 Moimtain limestone, in a limestone sink, K mile north 

 of Salt Mountain, in the NWK NWM, Sec. 34, T. 6 N., 

 R. 2 E., Clarke Covmty, Alabama. Collected by H. T. 

 and A. R. Loeblich, Jr. 



Figured hypotype (USNM P5838) from the Horners- 

 town formation, north bank of Shingle Rim, a tributary 

 to Crosswicks Creek, 1.0 mile north of New Egypt, 

 Monmouth Coimty, New Jersey. Collected by A. R. 

 Loeblich, Jr., and Norman Sohl. 



This species also occiu^ in the Aquia formation of 

 Virginia. 



Globlgerina triloculinoides Plummer 



Plates 40, Figures 4a-c; 41, Figures 2a-c; 42, Figures 2a-c; 

 43, Figures 5a-c; 8a-9c; 45, Figures 3a-c; 46, Figures 

 la-c; 47, Figures 2a-c; 52, Figures 3-7; 56, Figures 8a-c: 

 62, Figures 3a-4c 



Globigerina triloculinoides Plummer, Univ. Texas BuU. 2644, 

 p. 134, pi. 8, figs. lOa-c, 1926.— Jennings, Bull. Amer. 

 Paleontol., vol. 23, No. 78, p. 193, pi. 31, fig. 7, 1936.— 

 HoFKER, Rep. McLean Foram. Lab., No. 2, p. 15, pi. 2, 

 1955. — Shifflet, Maryland Dep. Geol., Mines and Water 

 Resources Bull. 3, p. 71, pi. 4, figs. 16, 17, 1948. 



Globigerina pseudolriloba White, Journ. Paleontol., vol. 2, No. 3, 

 p. 194, pi. 27, fig. 17, 1928. 



Globigerina triangularis White, Journ. Paleontol., vol. 2, No. 3, 

 p. 195, pi. 28, fig. 1, 1928. 



Globigerina velascoensis var. compressa White (not Globigerina 

 compressa Plummer, 1926), Journ. Paleontol., vol. 2, No. 3, 

 p. 196, pi. 28, fig. 3, 1928. 



Globigerina bulloides d'Orbigny, Jennings, Bull. Amer. Paleon- 

 tol., vol. 23, No. 78, p. 193, pi. 31, fig. 7, 1936. 



Globigerina linaperta Finlay, Bronnimann, Bull. Amer. Paleon- 

 tol., vol. 34, p. 164, pi. 2, figs. 7-9, 1952.— Bolli, U. S. 

 Nat. Mus. Bull. 215, p. 70, pi. 15, figs. 15-17, 1957. 



Globigerina stainforthi Bronnimann, Bull. Amer. Paleontol., 

 vol. 34, p. 171, pi. 3, figs. 10-12, 1952. 



Globigerina finlayi Bronnimann, Bull. Amer. Paleontol., vol. 34, 

 p. 166, pi. 2, figs. 10-12, 1952. 



Globigerina hornibrooki Bronnimann, Bull. Amer. Paleontol., 

 vol. 34, p. 163, pi. 12, figs. 4-6, 1952. 



GloboTotalia tortiva Bolli (new name for Globigerina velascoensis 

 var. compressa White, 1928; not Globigerina compressa 

 Plummer, 1926), U. S. Nat. Mus. Bull. 215, p. 78 (not pi. 

 19, figs. 19-21), 1957. 



Test free, composed of rapidly enlarging chambers in 

 a low trochospiral arrangement ; chambers subglobular, 



the two whorls of chambers visible on the flattened 

 spiral side, only the 3 to SK chambers of the final 

 whorl visible on the umbilical side, with the final one 

 occupying % to K the side; sutures distinct, depressed; 

 wall calcareous, finely perforate, surface prominently 

 reticulate; aperture interiomarginal, umbUical, with a 

 distinct and prominent lip, the aperture in some speci- 

 mens showing a tendency to become extraumbilical- 

 umbUical. 



Hypotypes range from 0.23 to 0.43 mm. in greatest 

 diameter and 0.15 to 0.33 mm. in thickness. 



Remarks: Qlohigerina triloculinoides Plummer is 

 characterized by the tripartite appearance of the um- 

 bUical side, with the exceptionally large and inflated 

 final chamber and the typical pitted or reticulate 

 surface. The aperture is typically umbilical, but in 

 some specimens extends somewhat more forward, tend- 

 ing to become extraumbilical-umbilical, as is true of 

 occasional specimens in many other species of Glo- 

 bigerina. 



An examination of a large suite of specimens from a 

 single locality shows considerable variation in minor 

 features, but these variations are obviously within the 

 limits of a single population. For this reason, we 

 consider as synonyms here certain of these variations 

 which have been given distinct names in the past even 

 though they occm- together in a single assemblage or 

 are of the same age. 



BoUi (1957, p. 70) considered Globigerina Jinlayi 

 Bronnimann a synonym of G. linaperta Finlay and G. 

 hornibrooki Bronnimann a synonym of G. triangularis 

 White. He considered G. stainforthi transitional be- 

 tween G. triloculinoides Plummer and G. pseudobul- 

 loides Plummer. Globigerina stainforthi, G. hornibrooki, 

 G. finlayi, G. triangularis, and G. -pseudotriloba White 

 aU are here considered synonyms of G. triloculinoides 

 Plummer as all have relatively few chambers, rapidly 

 increasing in size, and a coarsely reticulate surface. 



Globigerina linaperta Finlay is a middle Eocene 

 instead of a Paleocene species, and is characterized by 

 an almost equatorial aperture. The similarity to G. 

 triloculinoides Plummer in chamber development and 

 coarsely punctuate surface, and the tendency of some 

 specimens of G. triloculinoides to develop an extra- 

 umbilical aperture, strongly suggest that G. linaperta 

 is a descendant of the earlier G. triloculinoides. The 

 specimens referred to G. linaperta by Bronnimann 

 (1952) from the lower Lizard Springs are typical G. 

 triloculinoides, not linaperta, and are of Paleocene age. 



Globigerina pseudobulloides Plummer does not have a 

 coarsely reticulate surface, has more chambers per 

 whorl, a more gradual rate of increase in chamber size 

 and a more definitely extraumbilical apertm-e. 



Globigerina hornibrooki Bronnimann is probably a 

 synonym of G. triangularis White as was stated by 

 BoUi, but we regard both as synonyms of G. trilocu- 

 linoides. The type specimens of these species show a 

 more gradual increase in chamber size than does the 

 original figure of G. triloculinoides, as the type specimens 

 of G. triangularis White have 4 chambers in the final 



