The document describes several different mollusks and cnidarians. It provides details on the physical characteristics, habitats, and taxonomic classifications of various gastropods like Conus and Cypraea, bivalves like Perna and Meritrix, and cnidarians like Fungia, Favia, Gorgonia, Tubipora, Metridium, and Pennatula. The document also includes general information on the phylum Mollusca and its classes, as well as the characteristic features and classes of the phylum Cnidaria.

2. Conus:
• It is a highly carnivorous gastropods.
• Generally found below the low water and
considered as pests on the oyster beds.
• It injects poison into the body of the prey and
cause paralysis.
• Tongue is modified and bear and bear 3 -4
whorls, last one being largest.
• A pair of tentacles and eyes are present.
• Foot is long, sole like with which animal
efficiently attached on the rocky shore.

3. Phyllum: Mollusc
Class : Gastropod
Family: Conidae
Genus: Conus

4. Cypraea
• It is commonly known as ‘Cowry’.
• It is marine and found in rocky shores and
coral reefs.
• The shell is convolute, oval above and
flattened below.
• Surface of the shell is smooth, polished and
brightly colored.
• shell opening is long, narrow.
• In the young stages, the shell has a
prominent spire and long siphon.

5. Phyllum: Mollusc
Class : Gastropod
Family: Cypraeidae
Genus: Cypraea

6. Perna
• It is commonly known as Green mussel.
• Marine in their habitat, found more
extensively in rocky shore areas.
• Body enclosed in a wedge shaped shell
with two equal halves. It is pointed in front
and rounded behind.
• Byssal thread protrudes between two shell
valves, virtually by which it is attached to
stones and rocks.

7. • Foot is cylindrical, elongated with a ventral
groove, continuous with byssus pit.
• Pair of gills present.
• Sexes are separate. Gonads extend into
the mentle.
• Extensively used as test animal in
pollution related works.

8. Phyllum: Mollusc
Class : Bivalvia
Family: Mytilidae
Genus: Perna

11. General Characteristics:
• Mollusc are mostly marine. Many occur in
fresh water and some are terrestrial forms.
• Body of molluscs is un-segmented and
bilaterally symmetrical with a distinct head,
muscular foot and visceral mass.
• Body is commonly protected by an
exoskeleton calcareous shell of one or more
pieces which is secreted by mentle.
• Mentle (pallium) is a thin, fleshy fold of dorsal
body wall more or less covering the body. It
encloses a space, which is called mantle
cavity

12. Classification of Phyllum Mollusc
7 Classes:
1. Aplacophora
2. Polyplacophora
3. Monoplacophora
4. Gastropoda
5. Scaphopoda
6. Pelecypoda
7. Cephalopoda

13. Chiton:
• Chiton are commonly known as ‘sea cradles’
• They are marine molluscs of varying size
found attached to the rocks, empty shells and
corals between the tide marks.
• Body is elongated, bilaterally symmetrical
and dorsoventrally compressed consists of
shell, foot, mantle and visceral mass.
• The shell is calcareous, present on the
dorsal side and composed of eight
overlapping plates. Head is not distinct, eyes
and tentacles are present.
• Foot is ventral muscular with a flat side
extending along the whole length of the body.
It serves for creeping and adhering to
substratum.

14. • Mantle covers greater part of the body and
partly covers the edges of shell plates.
• Mouth and anus are at opposite ends.
• Sexes are separate. Development
includes trocophore larva.

16. Turitella:
• Commonly known as ‘sacred shell’.
• It is found distributed in intertidal zones of
sand and muddy shores and sometimes in
estuaries and backwaters.
• It has spirally coiled shell with more length
than breadth.
• Foot is conical and helps in efficient
burrowing.
• Head bears a pair of tentacles.
• It feeds on detritus particle.

18. Dentalium:
• Commonly known as ‘tusk shell’
• They are marine, found in sand at greater
depth.
• Body is bilaterally symmetrical and enclosed
in a tubular shell that opens at both ends.
• Mantle folds are fused ventrally to form a
tube enclosing a body.
• Head is bearing the mouth which is
surrounded by contractile tentacles with
sucker like ends.

19. • Foot is long and conical, provides through
the anterior opening of shell and used in
burrowing.
• Gills are absent, respiration by transverse
folds in the lining of mantle.

21. Arca:
• Commonly known as ‘arc shell’
• Found distributed in the intertidal and subtidal
zones of sandy shores. Sometime found
washed in great numbers in the shores.
• Shells bear raised and vertically angled
umbo.
• Bold lines are present on the surface of the
wall.
• Both the walls are hinged by special
ligaments and siphons are lacking. Ventral
side of the shell bears a row of teeth and the
arrangement is called homodentition.

23. Meritrix
• Commonly known as ‘back water clams’.
• Shells are strong, bear number of lines of
growth.
• Both the shells are hinged by ligaments.
• Two pairs of gills are present.
• It is a filter feeder and feeds on particulate
matter.
• These muscles have the tendency to
accumulate toxins present in
dinoflagellates.

29. Classification of Phyllum Mollusc
Class 1 Pelecypoda or Bivalvia
• Habitat: mostly marine
• They burrow in mud and sand.
• Symmetry: bilateral and the body is
laterally compressed.
• No distinct head
• Examples: Mussels, Unio, Mytilus,

30. Class 2 Gastropoda
• Habitat: These are either aquatic or
terrestrial
• They possess a spiral shell.
• The foot is large and flat.
• Head is well developed with tentacles and
eyes.
• Examples: Hilex (Snail), Limax (Slug), Pila
(Apple snail)

31. Class 3 Cephalopoda
• Habitat: mostly marine.
• They are adapted for swimming.
• The foot is modified into eight to ten long
tentacles in the head region.
• The shell is either external, internal or
absent.
• Examples: Octopus, Loligo, Sepia, spirula,
Nautilus

32. Class 4 Monoplacophora
• Habitat: exclusively marine
• Head is present without eyes and
tentacles
• Gills are external
• Excretion: by serially arranged nephridia

33. Class 5 Amphineura
• Habitat: mostly marine
• Body is elongated
• Eye and tentacles are absent
• Radula is present
• Examples; Chiton, Neomenia

34. Class 6 Scaphopoda
• Habitat: marine
• Body is bilateral symmetry elongated and
enclosed in tusk shell
• Foot is reduced
• Excretion: a pair of Kidney
• Examples: Cadulus, Dentalium

36. Study of Coelenterata

37. Characteristic features
• Coelenterata includes animal phyla Cnidaria (
true jellies, sea anrmones, corals, sea pens) and
Ctenophora (comb jellies).
• They are aquatic animals and are mostly found
in marine environments and few are found in
freshwater habitats.
• They can be solitary or live in colonies. Each
individual is a zooid. They are sedentary or free
swimming.
• These are typically invertebrate multicellular
organisms, which show a very simple level
tissue organization.
• They are diploblastic, with two layers of cells, an
outer layer called the ectoderm and the inner
layer called the endoderm.

38. • These organisms show two morphological forms
– Polyps and Medusa.

39. • The bodyform is radially symmetrical.
• The body has a single opening, through which
food is taken in and also waste is expelled out.
• The opening in the body is surrounded by
tentacles.
• Tentacles have special structures known as the
nematocysts which help in capturing and
paralyzing prey.
• Coelenterates do not have sensory organs.
• Respiration and excretion occur through simple
diffusion.
• circulatory system is absent.
• Asexual reproduction is seen in polyps, through
budding and sexual reproduction is seen in
medusa form, through gametic

40. Classes of Coelenterata
Class : Anthozoa
• They are exclusively polypoid
Class : Hydrozoa
• They exhibit polymorphism. There are two
main types of zoods, the polyp and
medusa
.
Class : Schyphozoa
• They are true medusae

41. Fungia:
• Commonly known as mushroom corals
• They are mostly solitary, marine in habitat,
some attaining 30 cm in diameter.
• They are found in various bright colours
including white, pink, red, purple, blue and
yellow.
• Large in size, discoid corallite, convex on
upper and concave in lower surface.
• Septa are numerous and connected together.
• Adult animal bears a single polyp with many

42. Phylum : Cnidaria
Class: Anthozoa
Family: Fungiidae
Genus: Fungia

43. Favia:
• They are colonial corals, either dome shaped
or flat.
• They are marine and reef building stony
corals.
• Favia was originated in Jurassic period and it
is still living today quite successfully.
• There is a great diversity of form even among
individuals of the same species.
• In most species, the corallites are plocoid and
in some, monocentric.
• septa and costae linked to the corallite wall
are well developed and covered by fine teeth.

44. Phylum : Cnidaria
Class: Anthozoa
Family: Mussidae
Genus: Favia

45. Gorgonia:
• Commonly known as sea fan.
• It is a marine, colonial shallow water
anthozoa.
• Colony is yellowish / reddish in colour and
consists of plant like branching stems and a
short main trunk attached to the substratum.
• Colony branches only in one plane in a
feathery manner.
• The base of the colony expanded to form
hold fast organ.
• Axial rod is made up of flexible horn like
material gorgonium which is ectodermal in

46. Phylum : Cnidaria
Class: Anthozoa
Family: Gorgoniidae
Genus: Gorgonia

47. Tubipora:
• Commonly known as organ pipe corals.
• It is a marine, colonial polyploid most
common in coral reefs.
• Colony is reddish in colour and consists of
large numbers of vertical CaCO3 tubes of
different sizes.
• The tubes are connected with transverse
platforms formed by fusion of polyps spicules
and contain polyps.
• Polyps are green in colour but skeleton
becomes dull red due to presence of iron
salts.

48. Phylum : Cnidaria
Class: Anthozoa
Family: Tubiporiidae
Genus: Tubipora

49. Metridium :
• Commonly known as Sea anemone.
• It is a marine form, large sessile, brightly
coloured solitary flower like form.
• Sessile polyp attached at the base to the surface
beneath it by an adhesive foot, called a basal
or pedal disc, with a column-shaped body
topped by an oral disc.
• Most are from 1 to 5 cm (0.4 to 2.0 in) in
diameter and 1.5 to 10 cm (0.6 to 3.9 in) in
length, but they are inflatable and vary greatly in
dimensions.
• The oral disc has a central mouth, usually slit-
shaped, surrounded by one or more whorls of

50. Phylum : Cnidaria
Class: Anthozoa
Family: metridiidae
Genus: Metridium

51. Pennaluta :
• Commonly known as Sea pen / sea feather.
• It is a marine, sedentary and colonial form.
• Colour is usually red and the fully developed
colony measures about 10 cm in height.
• The colony is elongated, feather-like and is
differentiated into a lower peduncle or stalk and
an upper rachis.
• The rachis is narow at two ends, dialated in the
middle and bears two rows of lateral branches—
the pinnules.
• Each pinnule is a long, slightly curved, flattened
and fleshy projection of the rachis and bears,
along its upper margin, a row of anthocodia—the
autozoids.

52. Phylum : Cnidaria
Class: Anthozoa
Family: Pennatuliidae
Genus: Pennatula