In this article we will discuss about Sepia:- 1. Habit and Habitat of Sepia 2. External Structures of Sepia 3. Coelom 4. Digestive System 5. Locomotion 6. Respiratory System 7. Circulatory System 8. Excretory System 9. Nervous System 10. Reproductive System 11. Development. Habit and Habitat of Sepia: Sepia is a typical representative of the class Cephalopoda. Members of this [...]
Definition: Torsion (twisting) is the rotation of visceral organs in anticlockwise direction through an angle of 180° on the rest of the body during larval development. The phenomenon takes place in the free-swimming (veliger) larva of gastropods and converts the symmetrical larva into an asymmetrical adult. Contraction of the larval retractor muscles and differential growth are possibly responsible for such [...]
In this article we will discuss about the phylogeny and phylogenetic relationship of phylum Mollusca. Phylogeny of Mollusca: The phylogeny of Mollusca is a controversial issue. It was previously argued that Mollusca originated from annelids, generally assumption based on the evidence of fossilized monoplacophorans. But this theory was largely rejected because the body structure of Neopilina galatheae has revealed a [...]