Bd. III: 9l 
THE FOSSIL FOKAMINIFEKA. 
9 
Cristellaria ci'epidula Avith the symmetrical and lenticular Cristellaria rotulata. The 
test is oblong and biconvex». The specimen from the Pecten- conglomerate is non- 
carinate and the final chamber is only slightly inflated while its septal face is com- 
paratively narrow. 
The Cristellariæ of which C. crcpidula and C. rotulata may be taken as the 
limit forms are among the most widely diffused of recent foraminifera. In the fossil 
state they range from the Silurian to the Post-tertiary deposits and are of frequent 
occurrence at all stages. 
Sub-Family Polymorphininæ. 
Genus Polymorphina, d’Orbigny, 1826. Test polythalamous, rounded and 
generally inequilateral in contour; segments few in number, set obliquely and more 
or less spirally disposed; aperture central and terminal. 
Polymorphina gutta, (d’Orbigny). 
Plate I. Figs. II and 12. 
Pyrulina gutta, n’ORBiGNY, Ann. Sei. Nat.. 1826, vol. VII, p. 267, pi. XII, figs 5 and 6. 
Polymorphina gutta, Brady, Rep. Chall., 1884 p. 560. 
Polymorphina gutta is but a very regular and pyriform variety of the common 
P. lactea, WALKER and Jacob. The material from the Pecten-conglomerate has 
yielded only one specimen and that has been rendered by fossilization so opaque 
that the chamber segments are not visible. I have no doubt however that the form 
is rightl}' referred to the genus Polymorphina and to the group of P. lactea. 
The Polymorphina; of which P. lactea is the central type are very widely distributed 
in recent seas but are perhaps most common in comparatively shallow water and in 
temperate latitudes. In the fossil condition these forms are met with fairly commonly 
from the Jurassic period down to Post-tertiary times. 
Family Rotalidæ. 
Sub-family Rotalinae. 
Genus Truncatulina, d’Orbignv, 1826. Test free or adherent, rotaliform; gener- 
ally more convex on the oral surface. Shell-wall coarsely porous; surface sometimes 
tuberculate; aperture a curved slit at the inner edge of the last segment, sometimes 
with an elongate neck and lip. 
2 — 091144 Schwedische Südpolar-Expediiipn igoi — rçoj. 
