40 



BULLETIN 161, UNITED STATES NATIONAL MUSEUM 



Test elongate, elliptical, periphery convex, the opposite faces con- 

 cave, ends of the chamber projecting; sutures fairly distinct, the 

 outer angle of each chamber projecting above the inner portion of 

 the adjacent next- formed chamber; wall with a granular, dull sur- 

 face ; apertural end with a projecting cylindrical neck, circular, with 

 a single, very thin, slightly bifid tooth. Length, 0.5-0.6 mm ; breadth, 

 0.25-0.3 mm; thickness, 0.15-0.18 mm. 



This species is not common, but it was found at a number of sta- 

 tions. It is easily distinguished by the partly rounded periphery of 

 the chambers and by the projecting lateral margins originally de- 

 scribed from the Tortugas. It has also been recorded at Samoa and 

 in the present collections occurs off Levuka, Fiji, 12 fathoms; off 

 Nairai, Fiji, 12 and 24 fathoms; Viva Anchorage, 3 fathoms; off 

 Vavau Anchorage, Tonga Islands ; and off Rutavu. 



SPIROLOCULINA CLARA, new species 



Plate 10, Figures 4, 5 



Test very much compressed, periphery truncate and concave, both 

 ends somewhat prominently projecting; chambers numerous, narrow, 

 the sides thickened and opaque, the central portion thin and trans- 

 lucent; sutures distinct, not much depressed, not limbate; wall 

 smooth ; aperture distinctly exsertecl, with a tooth or sometimes two 

 opposite ones. Length, 0.5-0.7 mm. ; breadth, 0.3-0.4 mm. ; thickness, 

 0.1 mm. 



Holotype. — Cushman Coll. No. 14781, from Rongelap Atoll, Mar- 

 shall Islands. 



This is probably the same as the form I have figured as " Spiro- 

 loculina depressa d'Orbigny." 5 



The species is abundant at the type locality, and is marked by the 

 peculiar transparency of the middle portion of the chamber giving 



Table 10. — Spiroloculina clara — material examined 



1 Key to abbreviations is given in Table 1. 



E U. S. Nat. Mus. Bull. 71, pt. 6, pi. 3, figs. 6 a, 6, 1917. 



