Molluscan regions and annelid segmentation
A typical molluscan organization comprises a mantle, visceral mass and a muscular foot whose form can be strongly modified.
Key knowledge
A typical molluscan organization comprises a mantle, visceral mass and a muscular foot whose form can be strongly modified. The radula occurs in many mollusks but is absent in bivalves. Annelids have serial body organization with repeated structures, while segment fusion and specialization alter the adult arrangement. These related broad clades show substantial physiological and life-cycle variation.
Conditions and scope
- Shells, larvae, circulatory systems and digestive structures have exceptions; no single representative applies to every species.
- Repeated external rings alone do not establish homologous internal segmentation.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Read mantle/foot/visceral-mass and bivalve exception plus annelid metamerism, circulatory exceptions and specialized gut-less tubeworms; excluded species counts and taxonomic ranks treated as timeless.
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Entry details
Permanent link to this entry ↗- Record identity
- uni-bio-mollusk-annelid-organization
- Revision
- core.1
- Structured reference record
- University core expansion