TROPICAL PACIFIC FORAMINIFERA OF "ALBATROSS" 45 



This species, like perforata, was described from rich collections taken 

 at a depth of 40-50 fathoms off Fiji and has not been obtained in any 

 of the other material. It is larger than perforata, and the outline of 

 the chambers in the early portion is very distinct in the two species. 



Genus MIMOSINA Millett, 1900 



Mimosina Millett, Journ. Roy. Micr. Soc, 1900, p. 547. 



Genotype. — By designation, Mimosina hystrix Millett. 



Test triserial in the young, later biserial; chambers with a single 

 acicular spine at the outer angle; wall calcareous, vesicular; aperture 

 of two parts, one rounded and nearly terminal, the other below near 

 the inner rim of the chamber, more elongate, arched. Recent. 



MIMOSINA PACIFICA Cushman 



Plate 12, Figure 8 



Mimosina pacifica Cushman, Contr. Cushman Lab. Foram. Res., vol. 9, p. 77, 

 pi. 8, figs. 3a, b, 1933. 



Test irregularly triserial except in the adult portion, which becomes 

 biserial, tapering from an acute initial end to the broad rounded aper- 

 tural end, nearly circular in end view; chambers distinct, inflated; 

 sutures of the early portion indistinct, later ones slightly depressed; 

 wall calcareous, finely perforate, the initial portion with short spines 

 which in the later portion become largely confined to the base of the 

 chamber; aperture double in the adult, a narrow slit at the base of the 

 inner margin of the last-formed chamber above, which is a low, elong- 

 ate, supplementary opening. Length of holotype, 0.35 mm. ; diameter, 

 0.25 mm. 



The types are from off Levuka, Fiji, 12 fathoms. 



This distinctive small species also occurs at Mokaujar Anchorage, 

 Fiji, and Rongelap Atoll, Marshall Islands. 



Genus CHRYSALIDINELLA Schubert, 1907 



Chrysalidinella Schubert, Neues Jahrb. fiir Min., vol. 25, p. 242, 1907. 

 Chrysalidina of authors (not d'Orbigny). 



Genoholotype. — Chrysalidina dimorpha H. B. Brady. 



Test tapering, triangular in transverse section, early chambers tri- 

 serial, later ones becoming uniserial; wall calcareous, perforate; 

 aperture in the adult cribrate, consisting of numerous rounded open- 

 ings scattered over the triangular apertural face. Miocene to Recent. 



This genus is directly derived from Reussella. The stages in de- 

 velopment are very nicely seen in material from the station at 40-50 

 fathoms off Fiji, and show that it has a very close connection with 

 Reussella at this station. As already noted it cannot have been derived 

 from Chrysalidina, as is held by some authors, as that very large 

 coarsely arenaceous genus belongs in the family Verneuilinidae. 



