TROPICAL PACIFIC FORAMINIFERA OF "ALBATROSS" 5 



temporarily during life, the convolutions are clearly visible, the whorls 

 being separated from each other by a raised limbate ridge representing 

 the former periphery of the test. Between the ridges, the slightly 

 depressed channels are dotted thickly by perforations, light-colored 

 dots on a dark background. From this side the test is scarcely dis- 

 tinguishable from tests of Spirillina limbata Brady. The opposite 

 face of the test presents a wholly different appearance. The periphery 

 slopes inward, in some specimens steeply, in others so gently that the 

 sloping periphery occupies as much as one-thud the diameter of the 

 test. The surface of this face is concave inside the inward-sloping 

 periphery, and the central part is covered more or less thickly by knobs 

 and pustules of shell material, thus obscuring or obliterating the 

 individual convolutions of the test. 



There is great variation in this species, particularly in the degree of 

 slope of the periphery and in the development of the beaded covering 

 of the concave face of the test. 



SPIRILLINA INAEQUALIS SEMIDECORATA Heron-Allen and Earland 



Spirillina semidecorata Heron-Allen and Earland, 1915, Trans. Zool. Soc. 

 London, vol. 20, p. 685, pi. 51, figs. 26-31. 



Because of its plano-concave shape with inward-sloping periphery, 

 this form seems related to Spirillina inaequalis Brady. It differs 

 in the fine transverse fluting present over the whorls of the concave 

 face and down over the sloping periphery. Only five specimens were 

 found. 



This form, here regarded as a subspecies of S. inaequalis, was 

 described originally from the Kerimba Archipelago as a distinct 

 species. 



SPIRILLINA LIMBATA Brady 



Spirillina limbata Brady, 1884, Rep. Voy. Challenger, Zoology, vol. 9, p. 632, pi. 

 85, figs. 18-21.— Flint, 1899, Ann. Rep. U.S. Nat. Mus. for 1897, p. 326, 

 pi. 71, fig. 5. 



This symmetrical and biconcave species is represented by rare 

 specimens in only three samples. It is characterized by its truncated 

 periphery and its channelled surface, each coil being marked by a 

 raised limbate ridge that represents the former periphery of the test. 

 Between the consecutive rings of this limbate spiral, the wall is 

 distinctly but finely perforate. No other ornamentation decorates 

 the test. 



SPIRILLINA SPINIGERA Chapman 



Spirillina spinigera Chapman, 1899, Journ. Linn. Soc. London, Zoology, vol. 

 28, p. 10, pi. 1, fig. 7; 1900, op. cit., vol. 28, p. 188, pi. 19, figs. 9, 10.— Rhum- 

 bler, 1911, Foram. Plankton-Exped., pt. 1, pp. 119, 150, pi. 7, figs. 3-8; 

 1913, pt. 2, p. 433.— Cushman, 1924, Carnegie Instit. Washington, Publ. 342, 

 p. 32, pi. 9, figs. 6, 7. 



