What are the external features of molluscs?

What are the external features of molluscs?

External features The most obvious external molluscan features are the dorsal epidermis called the mantle (or pallium), the foot, the head (except in bivalves), and the mantle cavity.

What features does a Mollusca have?

Main characteristics of Mollusca :

  • Unsegmented soft body with bilateral symmetry.
  • Presence of an internal or external shell.
  • A toothed tongue (made mostly of chitin) called the radula.
  • A mantle which is a fold in the body wall that lines the shell.
  • Muscular foot (and/or tentacles in some).

Is Frog a mollusc?

they are all in the same category of animals known as mollusks and are structurally similar.

Are Mollusca internal or external?

Molluscs that use such a system remain of one sex all their lives and rely on external fertilization. Some molluscs use internal fertilization and/or are hermaphrodites, functioning as both sexes; both of these methods require more complex reproductive systems.

Which characteristic is typical of molluscs quizlet?

phylum of organisms characterized by having a soft body, muscular foot, and (most often) a protective shell; 1)Bilaterally symmetrical.

Which of the following animal belongs to the phylum Mollusca?

The animals belonging to the phylum Mollusca are apple snail, pearl oyster, devil fish, tusk shell, etc.

What makes a Mollusca mollusc?

mollusk, also spelled mollusc, any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium carbonate shell secreted by a soft mantle covering the body.

Is fertilization in molluscs external or internal?

Molluscs have extreme variation in reproductive characteristics. A generic mollusc is dioecious with paired gonads. Eggs or sperm are released into the coelomic cavity and carried outside by ducts. Fertilization is external and the zygote develops into a gastrula and then a free-swimming trochophore larva.

Is fertilization internal or external in cnidaria?

However, basal animals, such as medusozoan cnidarians (i.e., jellyfish) in which plesiomorphic external fertilization would be expected in adult medusae [2], offer several interesting examples of disparate jellyfish species exhibit- ing internal fertilization.

What are the characteristics of Mollusca?

Bilaterally symmetrical, coelomate protostomia with spiral cleavage and soft un-segmented body, covered by a thick muscular fold, the mantle which secrets a single or many shells, and a radula in the oesophagus except Bivalvia, and ventral muscular foot for locomotion. 2. Habit and Habitat of Molluscs:

What is the morphology of a frog?

Morphology of frog Body of a frog is somewhat spindle-shaped, pointed anteriorly and rounded posteriorly. It is slightly flattened dorsoventrally. It is streamlined so that it offers least resistance while swimming. Body is divisible into distinct head, trunk and limbs.

What is the classification of mollusks?

Mollusca (mollusks) are classified into 6 classes according to their symmetry and the characters of food, shell, mantle, gills, nervous system, muscles, and radula. Class 1. Monoplacophora (Gr., monos, one+ plax, plate+ pherein, bearing) Body is bilaterally symmetrical and segmented. Mantle dome-shaped. The shell comprises a single piece or valve.

What are the sensory organs of molluscs?

The tentacles, eyes, osphradium, and statocysts act as the sensory organs. The sexes are separate in most of the molluscs but some species are hermaphrodites. Fertilization may be external or internal. They are generally oviparous with indirect development. Following are the classification of Mollusca: