View source for Columella

[[File:Fig 32.jpg|thumb|<font size="2">'''Fig. 1.''' Columellas. Transmitted light micrographs.
'''A-D:''' ''Kurnubia palastiniensis'' Henson. Upper Jurassic, Northeastern Morocco. '''A:''' transverse section near and almost parallel to the axis of coiling; '''B:''' axial section; '''C-D:''' oblique sections. Position of sections relative to the axial section marked by red lines. '''E:''' ''Borelis schlumbergeri'' (Reichel), axial section. Gulf of Aqaba. Recent. Note double columella in planispiral-fusiform shells. '''b:''' [[beam]]; '''bl:''' [[basal layer]]; '''col:''' [[columella]]; '''f:''' foramina; '''prp:''' [[preseptal passage]]; '''r:''' [[rafter]]; '''s:''' [[septum]]; '''sl:''' [[septulum]]; '''t:''' [[tunnel]]; '''wsut:''' whorl suture; (Hottinger, 2006; fig. 32 [http://paleopolis.rediris.es/cg/CG2006_M02/index.html] '''CC'''/BY-NC-SA)]]

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==Definition==
*''according to Hottinger (2006):''
'''COLUMELLA''' - the solid, trochospiral structure formed by the basal walls of spiral chambers coalescing around the coiling axis, as in many gastropod shells, or symmetrically poleward in planispiral - fusiform shells. May be thickened by secondary deposits or by an extensive thickening of a basal layer in the polar realm of the shell (alveolinids).  



==References==
Hottinger (2006), [http://paleopolis.rediris.es/cg/CG2006_M02/index.html Illustrated glossary of terms used in foraminiferal research]. [http://paleopolis.rediris.es/cg/uk-index.html Carnets de Géologie], [http://paleopolis.rediris.es/cg/CG2006_M02/index.html Memoir 2], ISSN 1634-0744                                                              
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