Mollusks Anatomy

The morphology and anatomy of modern bivalves have been much altered from those of ancestral mollusks which had a distinct anterior end with a mouth and a posterior end with an anus figure 1. The main body cavity is a hemocoel through which blood circulates.

Animal Kingdom Mollusks Bivalve Shell Anatomy Of A

Mollusks are a phylum of soft bodied invertebrate animals.

Mollusks anatomy. Most molluscs have a head with eyes and all have a pair of tentacles with sensors also on the head that detect chemicals vibrations and touch. Although basically marine bivalves and gastropods include freshwater species. Locomotion the foot is the organ of locomotion in land gastropods.

Let us find out more information about the anatomical characteristics of molluscs. Gastropods have also adapted to land with thousands of species living a fully terrestrial existence. Genital gland producing spermatozoa sperm or ova eggs depending on the sex of the mollusk.

The eyes of the giant squid are the largest in the animal kingdom almost the size of dinner plates. One of the special features of their body structure is the presence of a coelom. Radula plural radulae or radulas horny ribbonlike structure found in the mouths of all mollusks except the bivalves.

Only some species of molluscs have a brain. The coelom is a cavity present in body of molluscs which contains internal organs suspended from mesenteries. The foot although the basic form of the foot is a flat broadly tapered muscular organ which is highly.

As such their circulatory systems are mainly open. The anatomystructures of molluscs are complex in nature. There are over 50000 different types of mollusks alive today.

The mollusks have adapted to all habitats except air. Many mollusks have a hard external shell but others do not. Although molluscs are coelomates the coelom tends to be small.

In swimming and sessile forms however the foot is greatly reduced or greatly modified. The radula part of the odontophore may be protruded and it is used in drilling holes in prey or in rasping food particles from a surface. Gills respiratory organs located between the foot and the mantle formed of two layers of ciliated filaments which filter water and retain food particles.

External features pair of lamellate gills ctenidia a thick layer of glandular epithelium called mucus tracts or hypobranchial glands and the outlets for the digestive excretory and reproductive systems. Many mollusks have a hard external shell but others do not.

Animals Iii Pseudocoelomates And Protostome Coelomates