ART. 6 FORAMINIFERA: POLYMORPHINIDAE — CUSHP,/[AN AND 02AWA 49 



removed farther from the base; sutm^es much depressed, distinct^ 

 wall partly ornamented by longitudinal costae independent of the 

 sutures; aperture radiate. 



Polymorphina semicostata vfas first described by Marsson from the 

 uppermost Cretaceous of Riigen. His figures are apparently well 

 drawn, but seem to us not to give fully the details of the species, 

 especially as the arrangement of chambers is not drawn in sufficient 

 detail. Franke quite recently figured Marsson's specimen. His 

 figure shows a nearly quinqueloculine arrangement of chambers char- 

 acteristic of Gtittulina. Wright figures similar specimens from the 

 Cretaceous of Keady Hill, County Derry, Ireland. We have some 

 material from the Cretaceous of Rtigen, but could not find any speci- 

 men like the present one, and accordingly Marsson's figures are repro- 

 duced in the present paper. 



Distribution. — Only known from the Upper Cretaceous (upper 

 Senonian) of Riigen; very rare. 



GUTTULINA SADOENSIS (Cushman and Ozawa) 



Plate 37, figures 1, 2 



Sigmomorpha sadoensis Cushman and Ozawa, Contr. Cushman Lab. Foram. 

 Res., vol. 4, 1928, p. 17, pi. 2, fig. 11; Jap. Journ. Geol. Geogr., vol. 6, 

 1929, p. 73, pi. 13, figs. 9-11; pi. 16, figs. 2-4. 



Test more or less rhomboid, greatest breadth usually below the 

 middle, generallj^ triangular in end view; chambers numerous, elon- 

 gate, two to three times as long as broad, varying considerably in the 

 amount of overlapping, some of the specimens with the chambers 

 almost extending down to the base, others with the chambers con- 

 siderably above the base and the last-formed chamber in the adult 

 often not reaching back more than halfway to the base of the test; 

 chambers arranged in a quinqueloculine series, often becoming sig- 

 moi^al; sutures depressed, distinct; wall thick but translucent, 

 smooth; aperture radiate. 



Length of holotype 0.83 mm.; breadth 0.50 mm.; thickness 0.36 

 mm. 



The present species has rather slender, clavate chambers arranged 

 in a quinqueloculine series, which in later stages often tends to 

 become sigmoidal. We took the present species as the genotype of 

 Sigmomorpha, but we think it better to include it in Guttulina. It 

 is an intermediate form between Guttulina and Sigmomorphina. 



Distribution. — It is only known from the Pliocene of Japan, at 

 SaM'ane, Island of Sado in the Sea of Japan, where it is very abundant. 

 92709—30 4 



