12 BULLETIN 161, UNITED STATES NATIONAL MUSEUM 



The present specimens are thin-walled and nearly transparent, 

 with the pores appearing as white dots on the wall. The periphery 

 is lobulate and rounded, with no trace of a keel and no difference in 

 porosity between dorsal and ventral surfaces. The spire is small and 

 not raised above the surface of the dorsal side, and the umbilicus is 

 open. 



ROSALINA MICENS (Cushman) 



Plate 4, Figure 2 



Discorbis micens Cushman, 1933, Contr. Cushman Lab. Foram. Res., vol. 9, 

 p. 89, pi. 9, fig. 5.— Cushman, Todd, and Post, 1954, U.S. Geol. Surv. Prof. 

 Paper 260-H, p. 358, pi. 89, figs. 8, 9.— Todd, 1957, U.S. Geol. Surv. Prof. 

 Paper 280-H, p. 290 (tbl. 4), pi. 90, fig. 7. 



Rosalina micens has been reported thus far only from the Pacific — 

 in the Paumotu Islands, the Marshalls, and at Saipan. It seems to 

 be closely related to R. concinna, their separation being based on only 

 two transitional features : (a) in R. concinna, the outline is essentially 

 circular but, in R. micens, the circularity is indented where the final 

 chamber meets the previous whorl; (b) in R. concinna, the chamber 

 shape is a thin crescent but, in R. micens, it is a thick crescent with a 

 distinct angle in the middle of the concave side of the crescent. 

 Further study of these two forms is needed to determine whether 

 or not they are biologically distinct or merely forms of a single species. 

 In any case, it is a convenience to have separate names by which to 

 differentiate them. 



In the present material, R. micens is fairly well distributed, more 

 abundantly around the islands and atolls than in the deeper water 

 samples. 



ROSALINA RUGOSA d'Orbigny 



Plate 4, Figure 1 



Rosalina rugosa d'Orbigny, 1839, Voy. Amer. Merid., vol. 5, pt. 5, "Foramini- 



feres," p. 42, pi. 2, figs. 12-14. 

 Discorbis rugosa (d'Orbigny). — Cushman, Todd, and Post, 1954, U.S. Geol. 



Surv. Prof. Paper 260-H, p. 359, pi. 89, fig. 14.— Todd, 1957, U.S. Geol. 



Surv. Prof. Paper 280-H, p. 290 (tbl. 4), pi. 90, fig. 10.— Graham and 



Militante, 1959, Stanford Univ. Publ., Geol. Sci., vol. 6, no. 2, p. 94, pi. 



14, figs. 1, 2. 



Rare specimens from only a few samples are referable to this species. 

 It is characterized by its coarse pores and by its chambers becoming 

 progressively more inflated as added, so that the periphery is lobulated 

 and the sutures slightly indented. The aperture is rather widely 

 open beneath a projecting lip and extends from the umbilicus to the 

 periphery. Immature individuals show the characteristic coarse 

 pores, white in the dark translucent wall, but the inflation of the 

 chambers is absent or only slightly developed. 



