TROPICAL PACIFIC FORAMINIFERA OF "ALBATROSS" 13 



ROSALINA SUBBERTHELOTI (Cushman) 



Plate 4, Figure 4 



Discorbis subbertheloti Cushman, 1924, Publ. 342, Carnegie Instit. Washington, p. 

 33, pi. 10, fig. 1. 



This species was described from Samoa. Despite the inclusion of 

 Brady's "Discorbina bertheloti d'Orbigny sp." in this species by Cush- 

 man, it seems unlikely that they are the same. Rosalina subbertheloti 

 has a less regular sutural pattern on its concave surface, in this respect 

 resembling R. floridana, whereas Brady's illustrated specimen is more 

 like R. micens although not the same. R. subbertheloti is larger and 

 proportionally flatter than the other species of this genus in the present 

 material. 



It is represented rarely and found in only a few samples. 



ROSALINA VILARDEBOANA d'Orbigny 



Plate 3, Figures 2, 5 



Rosalina vilardeboana d'Orbigny, 1839, Voy. Amer. Merid., vol. 5, pt. 5, "Fora- 

 miniferes," p. 44, pi. 6, figs. 13-15. 



Test of average size for the genus, slightly compressed, biconvex, 

 usually more convex ventrally than dorsally, umbilicus large and 

 open, periphery angular, marked by a faint limbate band, outline 

 slightly lobulate around the last 2 or 3 chambers; chambers distinct, 

 coiled in a flat coil of about 2% whorls, 5 or 6 chambers comprising the 

 adult whorl, chambers not inflated dorsally, becoming progressively 

 more inflated ventrally as growth proceeds; sutures distinct, gently 

 curved, slightly depressed on dorsal surface, more deeply incised 

 between the inflated chambers on the ventral surface; wall calcareous, 

 smooth, dotted by the coarse perforations appearing white on the 

 nearly transparent wall, early chambers on the dorsal side lacking 

 the coarse pores in some specimens; aperture a low opening into the 

 umbilicus under the projecting edge of the final chamber, extending 

 nearly out to the periphery. 



Diameter about 0.35 mm., thickness about 0.20 mm. 



The original description of Rosalina vilardeboana, a species described 

 from around the Falkland Islands, mentions several features charac- 

 teristic of the present specimens : the russet tint of the early chambers, 

 as compared with the white color of the later ones, and the spire more 

 projecting and the wall less copiously perforated than in the related 

 species, R. globularis. 



This species is unlike other described species of Rosalina in that the 

 convexity is usually greater on the ventral than on the dorsal side. 

 That this difference in convexity might be a result of an accident of 

 attachment, rather than a true specific difference, has been considered. 

 Perhaps these specimens were attached by their dorsal surfaces (as 



