754 ON TWO GIG- ANTIC TYPES OF AKENACEOUS FOKAMINIFEBA. 
Figs. 4 & 5. Transparent sections, to illustrate the nature of the subcrystalline calcareous 
deposit filling the chambers, and the close setting of the sand-grains (s g , s g) 
in the compact portions of the test. — Magnified 45 diameters. 
PLATE LXXX. 
Fig. 1. General view of a transverse section of an average specimen, mounted in Canada 
balsam and seen as a transparent object, under a low power. — Magnified 5 
diameters. 
Fig. 2. A similar preparation from one of the compressed specimens alluded to at § 28. 
— Magnified 6 diameters. 
All the almond-shaped specimens are small, possibly not fully grown ; and 
if so, the composite test may have been less consolidated than in mature indi- 
viduals. This may account for their form. The arrows If If indicate a line 
on which pressure at the two sides appears to have caused the fracture of 
many of the layers. 
Fig. 3. Enlarged view of a portion of the transparent section shown in fig. 1. — Magni- 
fied 25 diameters. 
si, si. Spiral lamina. 
b, b. Points at which the ‘ primary ’ and the 4 accessory ’ skeleton are not in 
close approximation, and show their distinctness. 
fff- Imbedded Foraminifera in situ. 
Fig. 4. Longitudinal central section of a single layer near the periphery, showing the 
regularity of 4 tertiary ’ processes subdividing the chambers. 
si, si. Primary skeleton. 
s , s. Septa. 
t, s . Tertiary shelly processes affording perpendicular support. 
