Fig. 1. Canal systems. A: basic geometry of canals in simple rotaliid shells. Schematic, not to scale. Red: chamber plasm; yellow: canal plasm. B-C: during stages of retraction of the chamber plasm into the interior of the shell, the canal system provides motility to the organism by extruding the pseudopods through backdoors, so-called loop-holes. D-F: Challengerella bradyi Billman et alii. Gulf of Aqaba, Red Sea; Recent. SEM graphs. D: oblique-ventral view of umbilical face; E: dorsal (spiral) view; F: Epoxy resin cast of shell cavities showing canal system. G-H: Hottingerella chouberti (Hottinger), Northeastern Morocco, Lower Cretaceous. Schema after Hottinger, 1976, not to scale, and transmitted light micrographs. Note that the basic geometry with loop-holes in a shell lacking septal subdivision is similar to a rotaliid with chambers. a: aperture: ch: chamber; f: foramen; fol: folium; is: interlocular intraseptal space; isc: intraseptal canal; lh: loop-hole; m: mask; p: pores; rmfu: radial marginal furrows (open to the ambient environment for their full length prior to being covered by the next whorl); s: septum; sesut: septal sutures; sis: spiral interlocular space; spc: spiral canal; spmfu: spiral marginal furrow; spsut: spiral suture (between successive whorls); up: umbilical plate (general geometric position); vc: vertical canals (at umbilical chamber suture); x: approximate position of section; (Hottinger, 2006; fig. 26  CC/BY-NC-SA)
- according to Hottinger (2006):
PRIMARY SPIRAL-UMBILICAL CANAL is a more or less tubular or flattened space between the umbilical plates and the wall of the preceding coil or between plates, folia and the preceding coil; or between toothplates and the preceding coil.
Hottinger (1967), Foraminifères imperforés du Mésozoïque marocain, Notes et Mémoires du Service géologique, Rabat, N° 209, p. 5-168
Hottinger (2006), Illustrated glossary of terms used in foraminiferal research. Carnets de Géologie, Memoir 2, ISSN 1634-0744.
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