22 BULLETIN 104, UNITED STATES NATIONAL MUSEUM 



rod-like, occupying almost the entire height of the chamber; aperture, 

 a series of rounded openings at the base of the apertural face. 



Diameter, 0.75 mm.; thickness, 0.30 mm. 



D'Orbigny described this species from the "coast of Patagonia, to the 

 south of the Rio Negro." It is distinct from the other species of this 

 region in its thickening at the umbilical region in peripheral view and 

 the subacute margin and distinct sutures. 



ELPmOIUM LESSONU (d'Orbigny) 



Plate 9, figures 1-4 



Polystomella lessonii d'Orbigny, Ann. Sci. Nat., vol. 7, 1826, p. 284, No. 6; 



Voy. Amdr. Merid., vol. 5, pt. 5, 1839, "ForaminifSres," p. 29, pi. 3, 



figs. 1, 2. 

 Polystomella macella H. B. Brady (part) (not Fichtel and Moll), Rep. Voy. 



Challenger, Zoology, vol. 9, 1884, pi. 110, fig. 9 (not 8, 10, 11). 



Test of large size for the genus, compressed, periphery rounded, 

 margin very slightly lobulate, sides nearly parallel in peripheral 

 view, umbilical regions not mnbonate but occupied by a group of 

 irregular raised areas; chambers numerous, 20 to 22 in the last-formed 

 whorl, slightly inflated; sutures sigmoid, indistinct except as marked 

 by the retral processes which are prominent, elongate, rod-like usually 

 15 or more, extending nearly the whole width of the chamber, the 

 interspaces deep; aperture, a series of rounded openings at the base 

 of the apertural face. 



Diameter, 1.20 mm.; thickness, 0.35 mm. 



D'Orbigny's type locality for this species is given as "coast of 

 Patagonia, to the south of Rio Negro." His specimen was evidently 

 a young, immature specimen. It has proved to be abundant and very 

 well developed in Doctor Schmitt's collections from the Falklands. 

 at some stations the dominant species. 



This is one of the most beautifully sculptured species of the genus 

 and hardly to be confused with any other. Its distribution appears to 

 be rather limited so far as material available shows, as it has occurred 

 only in the South Atlantic. 



The young specimens are very close to the figure given by d'Orbigny, 

 but the adults have a more rounded periphery and more chambers. 



Brady's specimen from the Falklands noted above is this species 

 probably. 



ELPHIDIUM DISCOIDALE (d'Orbigny) 



Plate 8, figures 8-9 



Polystomella discoidalis d'Orbigny, in De la Sagra, Hist. Fis. Pol. Nat. 

 Cuba, 1839 "Foraminiferes," p. 56, pi. 6, figs. 23, 24.— Cusiiman, Publ. 

 311, Carnegie Instit. Washington, 1922, p. 56, pi. 10, figs. 3, 4; Publ. 344, 

 1926, p. 80. 



Test of medium size for the genus, somewhat compressed, periphery 

 subacute, margin slightly lobulate, sides convex in peripheral view, 



