FOBAMINIFEKA OF THE MINT SPRING CALCAREOUS MARL. 



143 



The only specimens from the Mint Spring 

 marl that can be referred to this species were 

 found at station 6447, Glass Bayou, Vicksbui^, 

 Miss. 



Genus ARTICULINA D'Orbigny, 1826. 

 Articulina byramensis Cushman. 



Articulina byramensis Cushman, U. S. Geol. Survey Prof. 

 Paper 129, p. 103. pi. 27, figs. 5, 6. 1922. 



Test of two portions, a basial triloculine por- 

 tion followed by a single linear chamber, the 

 earlier portion with the lip of the antepenulti- 

 mate chamber standing out free at the base, 

 that of the penultimate chamber covered by 

 the base of the last-formed one, the last cham- 

 ber rounded in transverse section or slight!}' 

 compressed, with a broadly flaring, slightly 

 downward curved lip; aperture rounded, 

 slightly longer than wide; surface of the test 

 with numerous longitudinal costae, sharp, 

 sometimes, especially in the final chamber, 

 anastomosing. Length 1.25 millimeters. 



This species, which I have described and 

 figured from specimens obtained in the Bvram 

 marl, also occurred in the Mint Spring marl at 

 stations 64.51 and 6452, Mint Spring Bayou, 

 Vicksburg, Miss. The specimens are very 

 similar to those from Byram, Miss., and show 

 the specific characters. 



Genus MASSILINA Schlumberger, 1893. 

 Massilina decorata Cushman, n. sp. 



Plate XXXIV, figure 7. 



Test much flattened, elliptical or oval, 

 slightly longer than wide, basal and aperturaJ 

 ends projecting, the apertural end narrowed to 

 a small cylindrical neck, nearly in the longi- 

 tudinal axis of the test; sutures rather indis- 

 tinct; surface dull white; periphery rounded, 

 the sides ornamented by very fine pits, giving 

 a finely granular appearance to the test. 

 Length 1 millimeter or less. 



Type specimens from station 6647, Chicka- 

 sawhay River 1| miles southwest of Baice, 

 Wayne County, Miss. This species also oc- 

 curred at the following stations : 



6452. Mint Spring Bayou, Vicksburg, Miss. 

 7671. "Brown's Cave," Leaf River, Miss. 



This species in some ways resembles some 

 of the specimens referred by Brady to Spiro- 

 loculina tenuis (Czjzek) . 



Genus TRILOCULINA D'Orbigny, 1826. 

 Triloculina peroblonga Cushman, n. sp. 



Plate XXXIV, figures 4, 5. 



Test much elongate, periphery rounded; 

 chambers rounded at the base; the apertural 

 end coming to or extending slightly beyond the 

 base of the previous chamber; aperture rounded 

 wnth a simple tooth and a slightly thickened 

 lip; sutures distinct; wall dull white, smooth. 

 Length 1.5 millimeters or less. 



Type specimen from station 6451, Mint 

 Spring Bayou, Vicksburg, Miss. 



One of the specimens figured shows the aper- 

 ture at each end, the last-formed chamber 

 evidently havmg failed to cover the aperture 

 of the preceding chamber, an unusual occur- 

 rence in this group. 



Triloculina sculpturata Cushman, n. sp. 



Plate XXXIII, figures 4, 5. 



Test about t'wiee as long as •wide; periphery 

 rounded or truncate; sutures indistmct; surface 

 peculiarly sculptured, in general formed of lon- 

 gitudinal costae with broad surfaces, together 

 with irregular comiections, fornung areolae; 

 aperture rounded, with a simple tooth. Length 

 0.5 millimeter. 



Type specimen from station 6451, Mint 

 .Spring Bayou, Vicksburg, Miss. This species 

 was also found at station 6447, Glass Bayou, 

 Vicksburg, Miss. 



In its qumqueloculine stage this species has a 

 somewhat extended neck, but in its adult char- 

 acter the apertm'e does not usually extend 

 beyond the base of the previously formed 

 chamber. 



Genus BILOCULINA D'Orbigny, 1826. 

 Bilocullna ornata D'Orbigny. 



Plato XXXIII, figure 7. 



Biloculina omatn D'(!)rbigny, Foraminiferes fossiles du 

 baesin tertiaire de Vienne, p. 2G(i, pi. 16, figs. 7-9, 

 1846. 



Test slightly longer than wide, each cham- 

 ber broadest toward the basal end; aperture 

 broadly rounded, the tooth somewhat bifid; 

 surface smooth, dull. Length 0.40 millimeter. 



Specimens that may be referred to this species 

 occurred in the Mint Spring marl at stations 

 6451 and 6452, Mint Spring Bayou, Vicksburg, 

 Miss. 



