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What are the six classes of Mollusca?

What are the six classes of Mollusca?

Classes in Phylum Mollusca This phylum can be segregated into seven classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Cephalopoda, and Scaphopoda.

What are the 3 Mollusca classes?

The major classes of living mollusks include gastropods, bivalves, and cephalopods (Figure below).

  • Gastropods. Gastropods include snails and slugs. They use their foot to crawl.
  • Bivalves. Bivalves include clams, scallops, oysters, and mussels.
  • Cephalopods. Cephalopods include the octopus and squid.

What are the four main classes of Mollusca?


Class Major organisms
Gastropoda all snails and slugs including abalone, limpets, conch, nudibranchs, sea hares, sea butterflies
Bivalvia clams, oysters, scallops, geoducks, mussels, rudists†
Polyplacophora chitons
Cephalopoda squid, octopuses, cuttlefish, nautiluses, Spirula, belemnites†, ammonites†

What is the oldest part of a bivalve shell?

The oldest point of a bivalve shell is called the beak, and the raised area around it is known as the umbo (plural umbones). The hinge area is the dorsum or back of the shell. The lower, curved margin is the ventral side.

What is the order of Mollusca?

Phylum Mollusca is classified into seven classes;

  • GASTROPODA (single shelled cowries, cones etc)
  • BIVALVIA ( two shelled like clams, mussels etc)
  • APLACOPHORA (solenogasters)
  • MONOPLACOPHORA (segmented limpets)
  • POLYPLACOPHORA ( or Amphineura as it was earlier called- Chitons)
  • SCAPHOPODA (tusk shells)

Is a moon snail a gastropod?

The Naticidae, more commonly known as the moon snail, belongs to the class Gastropoda and the order Littorinimorpha. Gastropods are a class of animals containing snails, slugs, limpets, and sea hares. The foot is unlike a human foot, but it does help the animal move around. …

How do you classify shells?

When scientists classify shells, they first put them into one of these basic categories: the univalves, or gastropods, with one shell (like a snail); and bivalves, which have a two-part shell (like a clam).

Which one have two shells joined together?

The shell of a bivalve is composed of calcium carbonate, and consists of two, usually similar, parts called valves. These are joined together along one edge (the hinge line) by a flexible ligament that, usually in conjunction with interlocking “teeth” on each of the valves, forms the hinge.

Which is the oldest part of a snail’s shell?

In anatomy, an apex (adjectival form: apical) is part of the shell of a mollusk. The apex is the pointed tip (the oldest part) of the shell of a gastropod, scaphopod, or cephalopod.

What class of mollusks is the best?

Class Scaphopoda: these mollusks have a very elongated body like their shell, which is shaped like a horn. These are also known as fang shells. This is one of the best known types of marine mollusks. Class Bivalve: are aquatic mollusks whose body is enclosed between two leaflets or shells.

What are the 7 classes of mollusks?

Mollusks have well developed body organs (nervous system, circulatory system, respiratory system, etc.) but lack body segmentation. There are seven classes of Mollusks: Monoplacophora, Polyplacophora, Aplacophora, Gastropoda, Scaphapoda, Bivalvia and Cephalopoda.

What are the different classes of mollusks?

There are several different classes of mollusk. The most common mollusks are the gastropods (e.g., snails and slugs), the cephalopod (e.g., octopus, squid and cuttlefish ) and the bivalve (e.g., clam, muscle, oyster and scallop).

How many classes of mollusks are there?

The study of mollusks is called malacology. There are four main classes in the phylum mollusca , gastropods , bivalve, cephalopod and Polyplacophora. Gastropods include nudibranches , slugs and snails. They compose over one third of the mollusk group and most are single spiral shells but some have no shells.