Planispiral
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/7f/Anisus_septegyrus1pl.jpg/220px-Anisus_septegyrus1pl.jpg)
Planispiral is a condition in which a tubicolous shell is coiled in a single horizontal plane and the diameter increases away from the axis of coiling. This term is usually used for describing gastropod shells. Many cephalopods and tubeworms can also have a planispiral shell (Allaby and Allaby, 1999).
References
- Allaby, A. & Allaby, M. (1999). "Planispiral". A Dictionary of Earth Sciences. Retrieved 2014-01-13.
External links
- v
- t
- e
Cephalopod anatomy
Types |
| ||||
---|---|---|---|---|---|
Features |
|
![Illex illecebrosus anatomy](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b4/Illex_illecebrosus_anatomy.jpg/60px-Illex_illecebrosus_anatomy.jpg)
![Pelagic octopus Tremoctopus](http://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Pelagic_octopus_Tremoctopus.jpg/60px-Pelagic_octopus_Tremoctopus.jpg)
![Dissected Sepia officinalis](http://upload.wikimedia.org/wikipedia/commons/thumb/0/0e/Sepia_officinalis_dissected.jpg/60px-Sepia_officinalis_dissected.jpg)
funnel
External anatomy |
|
---|---|
Internal anatomy |
limbs
Brachial crown | |
---|---|
Buccal region |
|
Occipital region |
|
Other parts |
- Chromatophores
- Photophores
- Nervous system
Developmental stages: Spawn → Paralarva (Doratopsis stage) → Juvenile → Subadult → Adult • Egg fossils • Protoconch (embryonic shell)