Phylum Mollusca
$\displaystyle \small \bullet$ This is the second largest animal phylum
$\displaystyle \small \bullet$ They are generally aquatic mostly marine, few freshwater and some are terrestrial.
$\displaystyle \small \bullet$ They are bilaterally symmetrical, triploblastic and coelomate animals with organ system level of organization.
$\displaystyle \small \bullet$ Body is unsegmented and covered with calcareous shell.
$\displaystyle \small \bullet$ The body has distinct head, muscular foot and visceral mass.
$\displaystyle \small \bullet$ A soft spongy layer of skin forms a mantle over the visceral mass.
$\displaystyle \small \bullet$ The body cavity is hemocoel. The coelom is reduced and represented mainly by the pericardial cavity, gonadial cavity, and nephridia.
$\displaystyle \small \bullet$ Mouth contains rasping organ, called radula helps in feeding.
$\displaystyle \small \bullet$ Circulatory system is open and respiration takes place by gills. Haemocyanin is their respiratory pigments
$\displaystyle \small \bullet$ Excretion is by paired metanephridia.
$\displaystyle \small \bullet$ Anterior head region consists sensory tentacles.
$\displaystyle \small \bullet$ They are usually dioecious and oviparous with indirect development.
$\displaystyle \small \bullet$ Fertilization is external or internal.
$\displaystyle \small \bullet$ Ex: Pila (Apple snail), Loligo (Squid), Octopus (Devil fish).
Phylum Echinodermata
$\displaystyle \small \bullet$ They are exclusively marine organisms.
$\displaystyle \small \bullet$ They have an endoskeleton of calcareous ossicles.
$\displaystyle \small \bullet$ They have organ system level of organization.
$\displaystyle \small \bullet$ Adults are radially symmetrical but larvae are bilaterally symmetrical.
$\displaystyle \small \bullet$ They are triploblastic coelomate animals.
$\displaystyle \small \bullet$ Body is unsegmented with various shapes: flat, star like, spherical or elongated.
$\displaystyle \small \bullet$ Digestive system is complete with mouth on ventral side and anus on the dorsal side.
$\displaystyle \small \bullet$ Presence of water vascular system is characteristic of echinoderms which helps in locomotion, capture and transport of food and respiration.
$\displaystyle \small \bullet$ Respiration takes place by papule or gills.
$\displaystyle \small \bullet$ Nervous system and excretory systems are absent.
$\displaystyle \small \bullet$ Sexes are separate
$\displaystyle \small \bullet$ Fertilization is external, development is indirect with free swimming larva.
$\displaystyle \small \bullet$ Ex: Asterias (Star fish), Echinus (Sea urchin), Cucumaria (Sea cucumber), Ophiura (Brittle star).
Phylum Hemichordada
$\displaystyle \small \bullet$ This is a phylum that contains marine deuterostome animals.
$\displaystyle \small \bullet$ This is a small phylum with only a 100 known species, with animals having a worm-like appearance.
$\displaystyle \small \bullet$ They are Solitary and colonial, mostly tubicolous, exclusively marine.
$\displaystyle \small \bullet$ They have organ system level of organization.
$\displaystyle \small \bullet$ They are bilaterally symmetrical, triploblastic and coelomate animals.
$\displaystyle \small \bullet$ Body is soft, fragile, vermiform and divisible into proboscis, collar and trunk.
$\displaystyle \small \bullet$ Digestive tract complete and have straight or U-shaped tube.
$\displaystyle \small \bullet$ Circulatory system is of open type, respiration takes place through gills.
$\displaystyle \small \bullet$ Nervous system is primitive comprising of an intra-epidermal nerve plexus.
$\displaystyle \small \bullet$ Excretory organ is proboscis gland.
$\displaystyle \small \bullet$ Sexes are separate, reproduction is by sexual mode.
$\displaystyle \small \bullet$ Fertilization is external. Development mostly indirect through a free swimming larva.
$\displaystyle \small \bullet$ Ex: Balanoglossus, Saccoglossus.
$\displaystyle \small \bullet$ This is the second largest animal phylum
$\displaystyle \small \bullet$ They are generally aquatic mostly marine, few freshwater and some are terrestrial.
$\displaystyle \small \bullet$ They are bilaterally symmetrical, triploblastic and coelomate animals with organ system level of organization.
$\displaystyle \small \bullet$ Body is unsegmented and covered with calcareous shell.
$\displaystyle \small \bullet$ The body has distinct head, muscular foot and visceral mass.
$\displaystyle \small \bullet$ A soft spongy layer of skin forms a mantle over the visceral mass.
$\displaystyle \small \bullet$ The body cavity is hemocoel. The coelom is reduced and represented mainly by the pericardial cavity, gonadial cavity, and nephridia.
$\displaystyle \small \bullet$ Mouth contains rasping organ, called radula helps in feeding.
$\displaystyle \small \bullet$ Circulatory system is open and respiration takes place by gills. Haemocyanin is their respiratory pigments
$\displaystyle \small \bullet$ Excretion is by paired metanephridia.
$\displaystyle \small \bullet$ Anterior head region consists sensory tentacles.
$\displaystyle \small \bullet$ They are usually dioecious and oviparous with indirect development.
$\displaystyle \small \bullet$ Fertilization is external or internal.
$\displaystyle \small \bullet$ Ex: Pila (Apple snail), Loligo (Squid), Octopus (Devil fish).
$\displaystyle \small \bullet$ They are exclusively marine organisms.
$\displaystyle \small \bullet$ They have an endoskeleton of calcareous ossicles.
$\displaystyle \small \bullet$ They have organ system level of organization.
$\displaystyle \small \bullet$ Adults are radially symmetrical but larvae are bilaterally symmetrical.
$\displaystyle \small \bullet$ They are triploblastic coelomate animals.
$\displaystyle \small \bullet$ Body is unsegmented with various shapes: flat, star like, spherical or elongated.
$\displaystyle \small \bullet$ Digestive system is complete with mouth on ventral side and anus on the dorsal side.
$\displaystyle \small \bullet$ Presence of water vascular system is characteristic of echinoderms which helps in locomotion, capture and transport of food and respiration.
$\displaystyle \small \bullet$ Respiration takes place by papule or gills.
$\displaystyle \small \bullet$ Nervous system and excretory systems are absent.
$\displaystyle \small \bullet$ Sexes are separate
$\displaystyle \small \bullet$ Fertilization is external, development is indirect with free swimming larva.
$\displaystyle \small \bullet$ Ex: Asterias (Star fish), Echinus (Sea urchin), Cucumaria (Sea cucumber), Ophiura (Brittle star).
$\displaystyle \small \bullet$ This is a phylum that contains marine deuterostome animals.
$\displaystyle \small \bullet$ This is a small phylum with only a 100 known species, with animals having a worm-like appearance.
$\displaystyle \small \bullet$ They are Solitary and colonial, mostly tubicolous, exclusively marine.
$\displaystyle \small \bullet$ They have organ system level of organization.
$\displaystyle \small \bullet$ They are bilaterally symmetrical, triploblastic and coelomate animals.
$\displaystyle \small \bullet$ Body is soft, fragile, vermiform and divisible into proboscis, collar and trunk.
$\displaystyle \small \bullet$ Digestive tract complete and have straight or U-shaped tube.
$\displaystyle \small \bullet$ Circulatory system is of open type, respiration takes place through gills.
$\displaystyle \small \bullet$ Nervous system is primitive comprising of an intra-epidermal nerve plexus.
$\displaystyle \small \bullet$ Excretory organ is proboscis gland.
$\displaystyle \small \bullet$ Sexes are separate, reproduction is by sexual mode.
$\displaystyle \small \bullet$ Fertilization is external. Development mostly indirect through a free swimming larva.
$\displaystyle \small \bullet$ Ex: Balanoglossus, Saccoglossus.
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