FORAMINIFERA OF THE ATLANTIC OCEAN 21 



" Polystomella acvleata" from the Vienna Basin. These are left for 

 a more intensive study of this genus now under way. Nothing of 

 the sort occurs so far as I have seen in material from the western 

 side of the Atlantic. 



For the type form of Eljphidium crispum (Linnaeus) see Cushman 

 and Leavitt.* 



ELPHIDIUM EXCAVATUM (Terquem) 



Plate 8, figures 1-7 



Polystomella excavata Terquem, Essai Class. Anim. Dunkerque, 1875, p. 25, 



pi. 2, figs. 2 a-f. 

 Polystomella umbilicatula Williamson (not Walker and Jacob), Rec. Foram. 



Gt. Britain, 1858, p. 42, pi. 3, fig. 81. 



Test of small size for the genus, much compressed, periphery 

 broadly rounded, margin entire or slightly lobulate, umbilical regions 

 usually slightly depressed, sometimes with one or more small, rounded 

 bosses; chambers few, 8 to 10 making up the last-formed coil, slightly 

 if at all inflated; sutures distinct, very slightly depressed, marked by 

 the very short, narrow, retral processes with wide openings, between 

 8 and 10 in number, usually rather even and distinct; wall smooth; 

 aperture composed of a row of small, rounded pores at the base of 

 the apertural face. 



Diameter, 0.40 mm.; thickness, 0.12 mm. 



This species described and figured by Terquem from off the Atlantic 

 coast of France seems to represent well a common species found on 

 the coasts of Belgium and about the British Isles. It is somewhat 

 like E. incertum (Williamson), but is more compressed, has the retral 

 processes more even and in larger numbers, and the umbilical region 

 is different. It has passed under the general name of "Polystomella 

 striaio-punctata" but as noted is not that species. Williamson's 

 figured specimen referred to above is probably the same as Terquem's 

 species. 



Var. selseyensis Heron-Allen and Earland, from off the southern 

 coast of England is probably a form of this with a somewhat more 

 open coil. 



ELPHIDIUM OWENIANUM (d'Orbigny) 



Plate 8, figures 10-12 



Polystomella oweniana d'Oribignt, Voy. Am6r. Merid., vol. 5, pt, 5, 1839, 

 "Foraminiferes," p. 30, pi. 3, figs. 3, 4. 



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

 subacute, margin entire, greatest thickness in peripheral view at the 

 umbilical regions which are not distinctly umbonate; chambers 

 numerous, distinct, not inflated, averaging about 15 in the last- 

 formed coil; sutures distinct, limbate, the retral processes elongate, 



•Contr. Cushman Lab. Foram. Res., vol. 5, 1929, p. 20, pi. 4, figs. 3, 4. 



