Molluscs belong to a type of animal with a very large number of species, with more than 80,000 living species and more than 35,000 known fossil forms estimated.
They have a solid, segmentless body, in which four main parts are distinguished (except in highly modified species):
- the head, with tentacles, eyes or other sensory organs;
- the visceral sac, with the digestive system, heart and reproductive organs;
- the foot, a muscular formation used for locomotion and digging, transformed into tentacles in cephalopods,
- and the mantle, a fold of the epidermis that surrounds the visceral mass and separates it from the shell.
The anus, secretory ducts and respiratory organs are usually in the mantle cavity.
The shell is secreted by the edge of the mantle and is composed of an external horny layer and an internal pearly layer of calcium carbonate.
Molluscs spread throughout all land, river and sea areas.
Some lack a shell and others have only a rudimentary calcareous excretion.
Examples of Shells
CLASSIFICATION OF MOLLUSCS
The arrangement of the different organs and body parts of mollusks can be different depending on the class to which they belong.
The main classes are the following:
Other information about Molluscs
- Introduction
- Monoplacophores
- Poliplacophores
- Scaphopods
- Gastropods
- Bivalves or lamelibranchs
- Cephalopods
Other information about fauna in Aragón:
A small list of species in Aragon would be the following:
| Vertebrates | Invertebrates |
|---|---|
MammalsBirdsReptilesAmphibiansFishes |
MetazoansProtozoa |
|
images about the fauna in Aragon. photographs on invertebrates. beneficial animals for agriculture. | |
Auch Aragon genießt eine vielfältige und abwechslungsreiche Natur, in der Pflanzen vorbeigehen, Tiere, Geologie oder Landschaften erreichen wir ein fantastisches Bestiarium, das in seinen Denkmälern lebt.
Die Informationen werden ohne einen Spaziergang durch die drei Provinzen nicht vollständig sein, mit Abschaltungen in einigen seiner spektakulären Landschaften wie Ordesa, der Moncayo, Monegros oder durch Widerspruch den Ebro.
Sie können sich auch den immateriellen widmen: von der Legendenzusammenstellung das gilt auch für das universelle Aragon.