30 PROTOZOA—RHIZOPODA CLASS I 
Family 3. Globigerinidae. Carpenter. 
Test free, calcareous, perforated by coarse tubules; monothalamous or poly- 
thalamous ; chambers globular, either irregularly disposed or imperfectly spiral. 
Of the two most important genera belonging to this family, Orbulina, d’Orb. 
(Fig. 32, 4), is unilocular, and Globigerina, VOrb. (Fig. 32, C), multilocular. The 
individual chambers 
usually conduct into a 
common central canal. 
In both genera the test 
is often covered with 
extremely delicate 
calcareous spines, 
which, however, are 
very easily broken 
off, and are never 
A, Orbulina wiiversa, Lam. Pliocene; Sienna, Italy. 6B, Sphaeroidina preserved in the fossil 
Austriaca, VOrb. Miocene Tegel; Baden, near Vienna. C, Globigerina con- state. These genera 
Gece Samco: ae Ne ae ee ino 
in modern deep-sea 
deposits (Globigerina ooze); they occur sparingly in Mesozoic formations, 
beginning with the Triassic, and first rise to importance during the late 
Tertiary period. 
Sphaeroidina, VOrb. (Fig. 32, B). Cretaceous to Recent. 

Fic. 32. 
Family 4. Rotalidae. Carpenter. 
Test calcareous, rarely arenaceous or silicious, finely or coarsely perforated, fre- 
quently with intermediate skeleton, free or attached, turbinate or discoidal in contour. 
Segments usually arranged in an elongated spire, although in some forms irregularly 
disposed. 
Discorbina, Park. Jones (Fig. 33, dA, Bb). Test coarsely perforated, tur- 
binoid. Inferior surface broad and flat; umbilicus often filled with deposit 
of intermediate skeleton. Cretaceous to Recent. 
Planorbulina, Park. Jones (Fig. 33, C). Test coarsely perforated, com- 
planate, usually attached, superior and inferior surfaces dissimilar ; early seg- 
ments arranged in depressed spire, subsequently becoming cyclical. Lias to 
Recent. The dOrbignyan sub-genera Truncatulina, Anomalina, Planulina, 
ete., are based upon different modifications in form. 
votalia, Lam. (Fig. 34, 4). Test finely perforated, with segments in 
turbinoid spire. Septa composed of two slightly separated lamellae, with 
anastomosing canals occupying the intermediate space. Basis often 
thickened by supplemental skeleton. (7?) Silurian. Upper Jurassic to 
Recent. 
Pulvinulina, Park. Jones (Fig. 34, B). Rotaliform, but septa single and 
without interseptal canal-system. Lower Lias to Recent. 
Endothyra, Phill. (Fig. 34, C). Test calcareous ; composed of an exterior 
coarsely perforated, and an interior compact layer consisting of minute grains 
of limey matter; polythalamous; irregularly spiral. General aperture 
