sacculina on crab

1. Phylum:Arthropoda
Sub phylum:Crustacea
Class:cirripedia

2. • Day (1935)was the first man who reported the life
history of sacculina.
• Sacculina is popularly known as ROOT HEADED
BARNACLE.
• It is a crustacean parasite which infect many
species of Marine crab.
• It is characterised for extreme parasitic
degeneration retrogessive
metamorphosis&parasitic castration.

4. • Adult sacculina is extremely degenerated.it is only a
tumour like fleshy mass which have no trace of
segmentation ,appendages,mouth and internal
organs other than gonads.
• It is attached to the ventral so of the abdomen with
the help of peduncle.
• Numerous root like processes arise from peduncle
which extends through the soft tissues of the host
through which absorption of the nutrient and
removal of the waste material takes place.

5. • Lower side of the sacculina posses an opening called
mantle opening which leads internally into a cavity
called mantle cavity.it serves as brood
chamber.also it sorrounds the gonads,nerve ganglion
and cement gland.
• It is a protogynous hermaphrodite.
• It contain paired testes and overy.
• Cross fertilization is the rule.eggs are stored in the
mantle cavity.sperm from another sacculina enters
the mantle cavity and undergo fusion.early
development also takes place in mantle cavity.'

6. LARVAL STAGES
• Development is indirect with 5 larval stages.
• 1 NAUPLIUS LARVA
• 2.CYPRIS LARVA
• 3.KENTROGEN LARVA
• 4.SACCULINA INTERNA
• 5.SACCULINA EXTERNA

8. NAUPLIUS LARVA
• First free swimming larva.
• Triangular in shape.
• contain 3pair of appendages for swimming.
• contain 2frontal lateral horns each contain a pair
of gland cells.
• contain numerous germ cells.
• mouth and alimantary canal is absent.
• it moults to become the next larva called cypris
larva.

9. NAUPLIUS LARVA

10. CYPRIS LARVA
• NAUPLIUS transforms into CYPRIS larva.
• Triangular in shape.
• it is enclosed in a bivalved shell.
• it contain seven pair of appandages.
• it also contain numerous germ cells.
• abdomen is reduced but it contain caudal spines.
• single eye persists.
• after a short free swimming life it get attaches to the
body of a crab.and then it transform into next larval
stage.

11. CYPRIS LARVA

12. KENTROGEN LARVA
• The shell and appendages are discarded.
• A new cuticle is secreted.a mass of germ cell is
enclosed by this cuticle.it looks like a sac.it is
attached to the body of the crab by the antennule.
• It develops a chitinous tube called dart.
• The dart pierces through the body of the crab.the
content of the kentrogen larva pass into the
body cavity of the crab through dart.

13. KENTROGEN LARVA

14. SACCULINA INTERNA
• It remains inside the crab.
• it is formed of a mass of germ cells sorrounded by
a cuticle.
• This mass is attached to the lower side of
theintestine of the crab and it gives numerous
roots which ramify the body of the host
• Due to its continues growth it is pushed out as a
swelling in the abdomen of the crab.This stage is
called SACCULINA EXTERNA.

15. SACCULINA EXTERNA
• It lies on the outer surface of the abdomen
of the crab.it develops into the adult
sacculina.

16. LIFE CYCLE

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