Notes from NEET topper
Phylum- Mollusca (2nd largest phylum)
• Habitat-terrestrial or aquatic(marine/ freshwater).
• Body division-covered by calcareous shell & isunsegmented with a distinct head, muscular foot, visceralhump.
• Special structure-soft & spongy layer of skin forms amantle over the viscera hump.
• Respiration & excretion-space between hump & mantle(mantle cavity) have feather like gills which performrespiration & excretion.
• Sense organ-anterior head has sensory tentacles.
• Feeding organ-mouth have file like rasping organ calledradula.
• Reproduction-usually dioecious & oviparous with indirectdevelopment.
• Eg- pila (apple snail), pinctada(pearl oyster)Sepia(cuttle fish),Loligo(squid),Octopus (devil fish), Aplysia(sea hare),Dentalium (tusk shell),Chaetuplura (chiton)
