ART. 6 FORAMINIFERA: POLYMORPHINIDAE — CUSHMAN AND OZAWA 133 

 SIGMOMORPHINA CRASSA (Roemer) 



Plate 35, figures 4, 5 



Polymorphina crassa Roemer, Neues Jahrb. f. Min. etc., 1838, p. 385, pi. 3, 



fig. 27.— Reuss, Sitz. Akad. Wiss. Wien, vol. 18, 1855 (1856), p. 250, 



pi. 8, fig. 82. 

 Polymorphina crassatina v. Munster, Neues Jahrb. f. Min., etc., 1838, 



p. 385, pi. 3, fig. 30. 

 GuttuUna robusta Reuss, Sitz. Akad. Wiss. Wien, vol. 18, 1855 (1856), p. 246, 



pi. 6, fig. 65. 

 Polymorphina problema d'Orbigny var. deltoidea Reuss, Denkschr. k. Akad. 



Wiss. Wien, vol. 25, 1865, p. 154, pi. 4, fig. 8. 

 Polymorphina insignis Reuss, Sitz. Akad. Wiss. Wien, vol. 18, 1855 (1856), 



p. 248, pi. 7, figs. 74, 75. 



Test broadly oval to oblong, greatest width above the middle; 

 chambers inflated, arranged at first in a quinqueloculine series, becom- 

 ing biserial later, each succeeding chamber removed much farther 

 from the base; sutures depressed, distinct; wall thick, smooth; aper- 

 ture radiate. 



Maximum length 2.25 mm.; breadth 1.60 mm.; thickness 0.45 mm. 



Sigmomorphina crassa is fairly large, and even a young specimen, 

 which may closely resemble GuttuUna problema in general features, is 

 much larger than an adult of that species. This circumstance has led 

 Reuss to give the present species several specific names in different 

 stages of growth. Our study of a large number of specimens 

 obtained from the German Oligocene, showed that Reuss's Polymor- 

 phina problema var. deltoidea is a young phase of P. crassa. His 

 GuttuUna robusta, together with Polymorphina (GuttuUna) crassatina 

 Munster, has one more chamber added. Polymorphina insignis, a 

 very large specimen attaining to 2.6 mm. in length, is the adult and 

 has the later chambers arranged in a sigmoid series as in Sigmomor- 

 phina crassa (Roemer) . 



Distribution. — The present species seems to be restricted to the 

 German Oligocene where specimens are fairly common. We have 

 abundant specimens from the upper Ohgocene of Ahnatal, near 

 Cassel, Germany. 



SIGMOMORPHINA SCHENCKI Cushman and Ozawa, new species 



Plate 35, figures 6 a, b 



Test compressed, broadly ovate, greatest breadth near the base; 

 chambers elongated, embracing, arranged in a clockwise sigmoid 

 series, each succeeding chamber slightly removed from the base; 

 sutures not depressed, distinct; wall rather thick, smooth; aperture 

 radiate. 



Length of holotype 1.20 mm. ; breadth 0.90 mm. ; thickness 0.40 mm. 



Eolotype. — (Cushman Coll. No. 10147.) From the Oligocene 

 (Keasey shale), Oregon. 



