Arthopoda (104)
Appendage
An appendage refers to a structure that extends from the main body
segment of the organism. Arthropods, which include insects, arachnids
(like spiders), crustaceans (like crabs and lobsters), and myriapods (like
centipedes and millipedes), have jointed appendages that serve various
functions essential to their survival and daily activities.
Appendages of Prawn
Appendages are externally projected parts of the body in the formation of
which vari-ous systems of the body take part. These develop generally at
right angles to the long axis of the body and serve as locomotory organs,
feelers, food seizers, manipulators and sex organs.
The appendages are jointed in all arthropods . Biramous appendages are
nineteen pairs; five pairs in the head, eight pairs in the thorax and six pairs
in the abdomen.
Cephalic Appendages of Prawn:
1. Antennules:
• These are beneath the eye stalk
• Each consist of protoprodite, which is made up of precoxa, coxa and
basis.
• Precoxa is very large and hollow.
• Cavity of precoxa lodges the statocyst
• The coxa is short and cylindrical.
,• It bears setae.
• The basis is longer than the coxa and lacks setae.
• It bears a pair of long slender processes which is called feelers.
• The smaller inner feeler bears olfactory setea.
Functions:
Sensory and tactile.
2. Antennae:
• The antennae belong to 3 segments. Each with one feeler.
• The protoprodite has two prodomere, the coxa and the basis.
• The coxa is small in size and bears the renal aperture on its inner margin.
• The basis bears two rami.
• One of them is called squama.
• Squama act as a balancer in swimming.
Functions:
Tactile and balance.
3. Mandibles:
• They belong to the 4th segment. Lie on the side of the mouth.
• They are very stout and highly calcified.
• The protopodite has two podomeres, te coxa and the basis.
• The coxa is very large and can be divided into two parts, the proximal
hollow apophysis and the distal solid head.
• Each mandibles bears three segmented mandibular palp that arises from
the outer margin of the head.
,• Exopodite is absent
Functions:
Cutting and crushing of the food.
4. 1st maxillae (maxillulae):
• Leaf-like, with two inner lobes acting as gnathobases and an outer lobe.
• Appendage of 5th segment.
• Coxa and basis are broad.
• Endoprodite forms a curved process bifurcated at the apex.
• Exopodite is absent.
Functions:
Tearing and passing the food to the mouth.
5. 2nd maxillae:
• Leaf-like, with a flat-tened scaphognathite.
• Present in the last cephalic segment.
• Coxa is small and incompletely divided into two representing a fusion of
coxa and precoxa.
• The basis is large.
• Endopodite is small and unjointed.
• Exopodite large, flattened, fan like.
• Bears sensory setae along its free margin.
Functions:
Masticatory and respiratory.
,U have to draw every figure, its very important..with labelling..
Thoracic appendages :
1. 1st maxillipeds:
, • These are foliaceous.
• The coxa and basis of their protoppodite extend inwards as two
ganthobases.
• Coxa bears externally a bilobed epipodite.
• The exo and endopodite are unjointed and bears setae.
Functions:
Respiratory, masticatory and sending the food to the mouth.
7. 2nd maxillipeds:
• The protopodite is represented by a coxa.
• Coxa is short and bears a setae on the inner side.
• It also bears a small epipodite and a gill on the outer border.
• Basis is short and is immovable joined with the endopodite which consists
of five podomeres : a)Ischium, b) Merus c) Carpus d) Propodus c)
Dactylus.
• Exopodite is long and slender.
Function:
Respiratory, feeding.
8. 3rd maxillipeds:
• The protopodite bears a three-jointed leg-like endopodite and a slen-der
un-jointed exopodite.
• A small epipodite is present.
• These are leg like appearance.
• The first podomere represents fused ischium and merus.
• The second carpus.
Appendage
An appendage refers to a structure that extends from the main body
segment of the organism. Arthropods, which include insects, arachnids
(like spiders), crustaceans (like crabs and lobsters), and myriapods (like
centipedes and millipedes), have jointed appendages that serve various
functions essential to their survival and daily activities.
Appendages of Prawn
Appendages are externally projected parts of the body in the formation of
which vari-ous systems of the body take part. These develop generally at
right angles to the long axis of the body and serve as locomotory organs,
feelers, food seizers, manipulators and sex organs.
The appendages are jointed in all arthropods . Biramous appendages are
nineteen pairs; five pairs in the head, eight pairs in the thorax and six pairs
in the abdomen.
Cephalic Appendages of Prawn:
1. Antennules:
• These are beneath the eye stalk
• Each consist of protoprodite, which is made up of precoxa, coxa and
basis.
• Precoxa is very large and hollow.
• Cavity of precoxa lodges the statocyst
• The coxa is short and cylindrical.
,• It bears setae.
• The basis is longer than the coxa and lacks setae.
• It bears a pair of long slender processes which is called feelers.
• The smaller inner feeler bears olfactory setea.
Functions:
Sensory and tactile.
2. Antennae:
• The antennae belong to 3 segments. Each with one feeler.
• The protoprodite has two prodomere, the coxa and the basis.
• The coxa is small in size and bears the renal aperture on its inner margin.
• The basis bears two rami.
• One of them is called squama.
• Squama act as a balancer in swimming.
Functions:
Tactile and balance.
3. Mandibles:
• They belong to the 4th segment. Lie on the side of the mouth.
• They are very stout and highly calcified.
• The protopodite has two podomeres, te coxa and the basis.
• The coxa is very large and can be divided into two parts, the proximal
hollow apophysis and the distal solid head.
• Each mandibles bears three segmented mandibular palp that arises from
the outer margin of the head.
,• Exopodite is absent
Functions:
Cutting and crushing of the food.
4. 1st maxillae (maxillulae):
• Leaf-like, with two inner lobes acting as gnathobases and an outer lobe.
• Appendage of 5th segment.
• Coxa and basis are broad.
• Endoprodite forms a curved process bifurcated at the apex.
• Exopodite is absent.
Functions:
Tearing and passing the food to the mouth.
5. 2nd maxillae:
• Leaf-like, with a flat-tened scaphognathite.
• Present in the last cephalic segment.
• Coxa is small and incompletely divided into two representing a fusion of
coxa and precoxa.
• The basis is large.
• Endopodite is small and unjointed.
• Exopodite large, flattened, fan like.
• Bears sensory setae along its free margin.
Functions:
Masticatory and respiratory.
,U have to draw every figure, its very important..with labelling..
Thoracic appendages :
1. 1st maxillipeds:
, • These are foliaceous.
• The coxa and basis of their protoppodite extend inwards as two
ganthobases.
• Coxa bears externally a bilobed epipodite.
• The exo and endopodite are unjointed and bears setae.
Functions:
Respiratory, masticatory and sending the food to the mouth.
7. 2nd maxillipeds:
• The protopodite is represented by a coxa.
• Coxa is short and bears a setae on the inner side.
• It also bears a small epipodite and a gill on the outer border.
• Basis is short and is immovable joined with the endopodite which consists
of five podomeres : a)Ischium, b) Merus c) Carpus d) Propodus c)
Dactylus.
• Exopodite is long and slender.
Function:
Respiratory, feeding.
8. 3rd maxillipeds:
• The protopodite bears a three-jointed leg-like endopodite and a slen-der
un-jointed exopodite.
• A small epipodite is present.
• These are leg like appearance.
• The first podomere represents fused ischium and merus.
• The second carpus.
