Phylum Mollusca

The shy, little, misunderstood animals. Hug a giant squid today.

I. Unifying Characteristics

    1. 80,000 species total (2nd largest phylum, Arthropods come first)
    2. Body of Foot, Visceral Mass, Mantle and Shell (exoskeleton)
    3. Mouth with Radula
    4. Protostomes, Bilateral, Tripoblastic, Reduced Coelom
    5. Respiratory by gills or lungs
    6. Sexes separate usually
    7. Larvae: Trochopore → Veliger → Juvenile
    8. First Evidence of a Coelom
    9. Basic Body Region
    1. Shell (mantle)
    2. Feet –highly modifiable, Flexible
    3. Odontophore "tooth" and "bones" –radula

 

II. Classification

    1. Class Monoplacophora (1 spp)

      2. Neopolina

    2. Class Aplacophora

      3. Solengasters

    3. Class Polyplacophora (600)

      4. Chitons

    4. Class Gastropoda (3500)

      5. Snails, slugs, nudibranchs

       

       

    5. Class Pelecypoda (Bivalvia) (10,000)

      6. Clams

    6. Class Scaphipoda (200)

      7. tooth shells

    7. Class Cephalopoda (600)

squid, octopus, cuttlefish