LARVAL FORMS OF MOLLUSCA.pptx

LARVAL FORMS OF MOLLUSCA BHY SHRUTI SINGH MSC 1ST SEM FROM GEVPG COLLAGE KORBA CHHATTISGARGH,Types of larva are found in mollusca

1. TOPIC - LARVAL FORMS OF MOLLUSCA Government E.V.P.G. College, Korba , (C.G.) Representated by – Shruti Singh Class – M.Sc. 1 st Zoology Guided by – Miss Poonam Pandey Mam

2. Introduction Defination Types of larva in Mollusca Conclusion R eference

3. Introduction MOLLUSCA DERIVED FROM WORD MOLLIS. IT MEANS SOFT BODY ARISTOTLE FIRST USE MOLLUSCA FOR CUTTLE FISH IT IS SECOND LARGEST PHYLUM OF ANIMAL KINGDOM SOFT BODY ANIMAL WITH SHELL AND VENTRAL MUSCULAR FOOT FERTILISATION INTERNAL OR EXTERNAL DEVLOPMENT DIRECT OR INDIRECT

4. DEFINATION ‘’An Animal (as a clam,snail or octopus) that lives mostaly in water and has a soft body usually enclosed in a shell countaining calcium mollusk.’’

5. Types of Larva 3 Types of larva are found in mollusca

6. Trochophore Larva Pear shaped larva Length 0.5 mm Body divided into 3 regions. Prototroch,teleotroch and growthzone Prototroch- They developed into Apical plate and Mouth Body devided into two unequal part Protomium found in Upper side and mouth and anus are located in lower side It also called Velum ,it is a swimming organ Teleotroch - They developed into Anus Region Growthzone – zone between Mouth and Anus

7. Veliger Larva Veliger larva present in preoral ciliate area Veliger larva Covered with Shell In veliger larva heart and kidney are presented in interior end Cilia present and help to locomotion 3 rings of cilia in head Rediment foot present in ventral side Mantal folds developed into tubular manteles Cerebral ganglia and cephalic tuft present in upper side Torsion formation in developmental period

8. Glochilium Larva Mouth and Anus are absent Byssus thread like structure present Undeveloped legs present Length 0.1mm-0.5mm Found in freshwater Shell volve cover larva mentle Bounded with two volves

9. CONCLUSION Free swimming larva are usually formed when the adult is fixed Internal parasite generally have a stage which may be called larval stage in which they are transferred either by active or passive migration to a new host

10. R eference I nvertebrate zoology by R.L. KOTPAL Biology of Mollusca by DR. KHANNA And P.R. YADAV

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