FOKAMINIFERA OF THE MINT SPRING CALCAREOUS MARL. 



133 



Polymorphina cuspidata H. B. Brady. 



Plate XXX, figures 9, 10. 



Polymorphina sororia Reuss var. cuspidata H. B. Brady, 

 Challenger Rept., p. 5G3, pi. 71, figs. 17-19; pi. 72, 

 fig. 4, 1884. 



Test elongate, fusiform, composed of a few 

 chambers, initial end with a prominent sharp, 

 elongate spine, apertural end bluntly pointed; 

 surface smooth; sutures somewhat depressed; 

 aperture radiate. Length 1.5 millimeters or 

 less. 



There are several specimens from station 

 6447 (Glass Bayou, Vicksburg, Miss.) which 

 are very close to this form as figured by Brady 

 in the Challenger report. The relation of this 

 form to P. sororia Reuss seems very problem- 

 atic, and I have given it specific rank. It is 

 also represented in the Mint Spring marl by the 

 variety described below. 



Polymorphina cuspidata H. B. Brady var. costulata 

 Cushman, n. var. 



Plate XXXI, figure 1. 



Variety differing from the typical species in 

 the surface ornamentation, which consists of a 

 few longitudinal costae, rather widely sepa- 

 rated from each other. 



Type specimen from station 6452, Mint 

 Spring Bayou, Vicksburg, Miss. 



Polymorphina vicksburgensis Cushman, n. sp. 



Plato XXXI, figure 2. 



Test elongate, fusiform, broadest near the ini- 

 tial end, which is subcircular in transverse sec- 

 tion, the later portion becoming compressed and 

 narrower, initial end bluntly pointed, or with a 

 short spine ; chambers becoming shorter toward 

 the apertural ends in the adult; surface smooth, 

 or with very slight longitudinal costae; sutures 

 not depressed but often standing out as clearer 

 areas in side view; aperture radiate. Length 

 1.5 millimeters or less. 



Type specimen from station 6451, Mint 

 Spring Bayou, Vicksburg, Miss. This species 

 occurs also at station 6448, Glass Bayou, Vicks- 

 burg, Miss. 



This seems to be different from the other de- 

 scribed species of this genus and may be dis- 

 tinguished especially by the cuspidate initial 

 end and the peculiar change in shape from the 

 rounded early portion to the narrow, com- 

 pressed last-formed portion. 



Polymorphina spinosa (D'Orbigny) Egger. 



Plate XXXI, figure 5. 



Glohiilina spinona D'Orbigny, Foraminif&res fossiles du 

 ba.ssin tertiaire de Vienne, p. 230, pi. 13, figs. 23, 24, 

 184(1. 



Polymorphina spinosa (D'Orbigny) Egger, Neues Jahrb., 

 1857, p. 292, pi. 14, figs. 9, 10, 

 H. B. Brady. Parker, and Jones, Linnean Soc. Lon- 

 don Trans., vol. 27, p. 243, pi. 42, figs. 36a, b, 1870. 



Test rounded, irregular; chambers few; sur- 

 face covered with numerous short, projecting 

 spines which seem to be hollow where broken. 

 Length 1 millimeter or less. 



Rare specimens were obtained at the follow- 

 ing stations : 



6447. Glass Bayou, Vicksburg, Miss. 

 6451. Mint .Spring Bayou, Vicksbiu'g, Miss. 

 6647. Chickasawhay River IJ miles southwest of Boice, 

 Miss. 

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



This species was originally described by D'Or- 

 bigny from specimens collected in the Vienna 

 Basin, and the specimens from the Mint Spring 

 marl, except that they are more irregular in 

 form, agree at least in the ornamentation of the 

 surface. 



Genus UVIGERINA D'Orbigny, 1826. 



Uvigerina byramensls Cushman. 



Uviejerina hi/ramenMs Cushman, U. S. Geol. Survey Prof. 

 Paper 129, p. 95. pi, IS, fig. ,5, 1922. 



Test minute, elongate, somewhat fusiform, 

 initial end pointed; chambers numerous, dis- 

 tinct; sutures depressed; surface ornamented 

 by longitudinal costae, rather thin and sharp; 

 the last-formed chamber more distinct than 

 the rest, the inner side concave, the other two 

 sides slightly convex, giving a generally trian- 

 gular section, the surface of the last-formed 

 chamber smooth; the apertural end produced 

 into a short cylindrical neck witn a slight lip, 

 the aperture circular. Length 0.25 to 0.40 

 millimeter. 



This species, originally described from speci- 

 mens collected in the Byram marl, has been 

 found at all but one of the stations in the Mint 

 Spring marl, as follows: 



6447. Glass Bayou, Vicksburg, Miss. 



64.^)1, 64.')2. Mint Spring Bayou, Vicksburg, Miss. 



6647, Chickasawhay River IJ miles southwest of Boice, 

 Miss, ' 



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



The characters that distinguish this species 

 seem to be very constant, and the last-formed 



