24.6 SYSTEMATIC PALTiONTOLOGY 



Occurrence. — ISTaxjemoy Foematiox. Woodstock. Aquia Fokma- 

 TiON. Upper Marlboro. 



Collections. — Johns Hopkins University, Maryland Geological Survey. 



PoLYMOEPHiXA COMPHESSA d'Orbigny. 

 Plate LXIII, Fig. 10. 



Polymorpliina compressa d'Orbignj', 1S46, Foram. Fossiles Vienne, p. 253, pi. xii, 



figs. 32-34. 

 PolymorpMna compressa Brady, Parker and Jones, 1870, Trans. Linn. Soc. London, 



vol. xxvii, p. 227, pL xl, flg. 12, a-f. 

 Polymorpliina compressa Bagg, 189fi, BulL 141, U. S. Geol. Survey, p. 92. 

 PolymorpMna compressa Bagg, 1898, Bull. Amer. Pal., No. 10, p. 29, pi. iii. ftg. 1. 



Description. — The shell or test of Polymorpliina compressa is oblong, 

 flatly compressed, inequilateral, with numerous fusiform chambers ar- 

 ranged in a double series. These are somewhat inflated and the sutures 

 depressed. The surface of the shell is sometimes beautifully striated 

 longitudinall}^, at others smooth or faintly striated. The aperture is 

 variable, sometimes labyrinthic or porous but usually simple, circular 

 and coronate. Its length is very variable, in our specimens from 0.82 

 to 1.3 mm., with a breadth of 0.43 mm. 



This species is very common in the Miocene of Maryland at Fium 

 Point, Jones Wharf, etc., and also in the Miocene of Virginia. It is, 

 however, not abundant in the Eocene. It has been identified from a 

 well-boring in Norfolk, Va., at a depth of 685 feet. Professor Brady 

 compares this form with its relatives as follows: 



"In general terms Polymorpliina compressa may be said to include the 

 less regularly Textulariform varieties of the genus, its nearest allies 

 being Polymorpliina complanata d'Orbigny; Polymorpliina froncliformis 

 S. V. Wood; and Polymorpliina cylindroides Eoemer. Of these the first 

 is distinguished by an exceedingly regular and equilateral Textularia- 

 like disposition of the segments, and Polymor pinna frondiformis by its 

 even larger dimensions and its surface-ornament of interrupted costae 

 or tubercles; whilst Polymorpliina cylindroides has a long tapering test, 

 less compressed than that of the present species and composed of a 

 small nnml)er of nearly erect segments. 



