Figure 68: Milioline coiling.
Schematic, not to scale. Note the coiling mode: only two chambers per whorl. Chamber lumina green, coiling axes black.
Foramina aligned in the apertural axis (red).
A: quinqueloculine mode of coiling: for each new chamber the coiling axis rotates 72° around the apertural axis. B: triloculine mode of coiling:
for each new chamber the coiling axis rotates 120°. C: biloculine mode of coiling: the coiling axis does not rotate.
a: aperture; cax: coiling axis; chs: chamber suture; mt: miliolid tooth.