PKOCEEDINGS OF THE NATIONAL MUSEUM vol.77 



In the general outline, it resembles Japanese Pliocene Sigmomor- 

 phina kotoi, but it is much larger and the chambers broader compared 

 with the length. It more or less resembles Sigmomorphina crassa 

 from the German Oligocene, but it has an advanced sigmoid arrange- 

 ment of chambers, and the chambers are much elongated. 



The species is named for Dr. H. G. Schenck of the Geological 

 Department of Stanford University. 



SIGMOMORPHINA KOTOI Cushman and Ozawa, new species 



Plate 35, figures 7 a, h 



Test compressed, ovate, broadly rounded at the base, tapering 

 toward the aperture, periphery somewhat angulate; chambers more 

 or less compressed, elongated, arranged in a clockwise sigmoid 

 series, each succeeding chamber slightly removed from the base; 

 sutures not depressed, distinct; wall smooth, translucent; aperture 

 radiate. 



Length of holotype 0.65 mm. ; breadth 0.40 mm. ; thickness 0.17 mm. 



Holotype. — (Cushman Coll. No. 11848.) From the upper Pliocene, 

 Natsukawa, in Province of Echigo, Japan. 



The characteristic feature of the present species is its ovate test 

 composed of elongated chambers which extend down to the base. 

 The species is named for Emeritus Prof. B. Koto, Imperial University 

 of Tokyo, Japan. 



Distribution. — Known onl}^ from the upper Pliocene of Japan. 



SIGMOMORPHINA TRINITATENSIS Cushman and Ozawa, new species 



Plate 36, figures 1, 2 



Test elongated, greatest breadth near the base, broadly rounded at 

 the base, uniformly tapering toward the acute apertural end; cham- 

 bers elongated, more or less cylindrical, embracing, arranged in a 

 clockwise sigmoid series; sutures not depressed, distinct; wall rather 

 thick, smooth; aperture radiate. 



Length of holotype 1.45 mm. ; breadth 0.90 mm. ; thickness 0.55 mm. 



Holotype. — (Cushman Coll. No. 11849.) From the Eocene, Hermit- 

 age quarry, Dumfries Road, Trinidad, British West Indies. 



The elongated test, somewhat like an isosceles triangle in its side 

 view, is very characteristic of the species. 



Distribution. — In addition to the Trinidad specimens, we have a 

 very similar specimen from the Eocene of Vincentown, N. J. 



SIGMOMORPHINA BORNEMANNI Cushman and Ozawa, new species 



Plate 36, figures S a, b 



Polymorphina dilatata Retjss, Zeitschr. deutsch. geol. Ges., vol. 3, 1851, 

 p. 83, pi. 6, fig. 49. 



Test compressed, equilaterally triangular with rounded peripheries 

 and angles, initial end slightly produced, margin thin and rather 



