Thursday, 30 August 2012


1.KAPPA PARTICLES-In conjugation the particles that survive is called killers and other are called sensitive. The one which survive are called killers and other self-replacting the cytoplasmic bodies are called kappa particles.These are associated with the production of a killing substances ,paramecin. The kappa particles diffuses out into the surrounding water and causes the death  of kappa particles it was found that a dominant gene in nucleus is necessary for kappa to exist,multiply and produce paramecium.
2.Pi particles-These are mutant forms of kappa particles. They do not release any toxic substances meant for killing those which are without such particles.
3.Mu PARTICLES-These particles are also killers and kill the mate without such particles, during conjugation.
4.LAMBDA PARTICLES-These are borne by killer paramecia and causes the sensitive paramecia to lyse or disintegrate.

Tuesday, 28 August 2012


The medusa is carnivorous.The food includes minute worms.These are capture by nematocysts-bearing tentacles and ingested by the highly contractile mouth.The prey is digested exclusively in the stomach.The digestion is both extracelluiar and intracellular like that of the hydranth. The digested food is diatributed to the entire medusa through the system of the radial and circular canals.


The elimination of soluble metabolic wastes from the protozoan body usually occurs by diffusion. The excreation by diffusion through the whole surface of the body takes place in marine and endoparasitic protozoans. In fresh water forms where the contractile vacuoles perform the function of osmoregulation some soluable wastes are also expelled with the outgoing water.

Sunday, 26 August 2012


The cytoplasm is commonly divided into two areas-the peripheral ectoplasm and the central endoplasm. The endoplasm contains the organelles found in metazoan cells,including mitochondria,golgi bodies,. The structures like trichocysts contractile vacuoles ,stigmas,which are exclusive of protozoa are seen in certain individuals.

Friday, 24 August 2012


Fungia are commonly called as 'Mushroom coral'. It is large and solitary coral. The skeleton or the corallite is discoid and convex on the upper and concave on the lower side.The numerous septa are small calcareous rods,the synapticulae. The ypung polyp,called anthocyathus, is attached by an anthocaulus,but the adult is free, large and lies at the bottom. It bears short tentacles and is without siphonoglyph.

Tuesday, 21 August 2012


The skin serves as protective covering ,the skin act as respiratory function.The capillaries containing the haemocoelomic fluid extends in between the cells of the epidermis .The carbon -di-oxide of the haemocoelomic fluid passes out and the oxygen dissolved in water .The skin is always kept wet by the surroundings water.The mucus secreated by the epidermal slime glands also prevents it from drying on exposure.

Sunday, 5 August 2012


Balantidium is a trichostomatid ciliated parasite,inhabiting the intestine of man,pigs,sheep etc. They are present in large numbers in the rectal contents of frog.The organism is large and ovoid and measures about 60-70mew. The entire outer surface is covered by longitudinal,slightly spiral rows of cilia. At the anterior end is a vestibule leading to the cell mouth or cytostome. it is lined by longer cilia. The cytoplasm includes two contractile vacuoles a macronucleus and food vacuoles. Nutrition is holozoic and the undigested residue is left by cytopyge.Reproduction takes place by asexual binary fission .Infection takes place through cysts in contaminated food and water


Friday, 3 August 2012


CHOANODERM-The gastrodermis consists of a single layer of flagellated cells,the choanocytes. The choanocyte is an ovoid cell with free end bearing a transparent contractile collar. The collar surrounds a single long flagellum which arises from a basal granule. The nucleus lies at the centre of its cell body . The choanocytes are used in feeding and for ensuring the flow of water within the animal,s body.

Wednesday, 1 August 2012


Chalina is a deep-water form and orange,yellowish brown or red in colour.The sponge is popularly known as the mermaid,s gloves" or "dead-man,s finger,s perforated with oscula. The skeleton consists of spongin with siliceous spicules embedded in it.When it is broken from its stalk and washed ashore it does not occur in shallow waters.