Noun:

ஈரல் தட்டைப்புழு இடைப்பருவம்,

cercaria's Usage Examples:

For example the free swimming cercaria and miracidia use highly specialized sensory organelles to locate their hosts.

The cercaria is just visible to the naked eye and has an oval or discoidal body and usually a long tail of variable form.

What determines the origin of the cercaria rather than a new generation of rediae is unknown.

c, Nearly ripe cercariae; cc, cystogenous cells; dr, daughter-redia; dt, limbs of the digestive tract; f, head-papilla; h, eye-spots; h', same degenerating; k', germinal cell; 1, cells of the anterior row; m, embryo in optical section, gastrula stage; n, pharynx of redia; o, digestive sac; oe, oesophagus.

D, An adult redia, containing a daughter-redia, two almost mature cercariae, and germs.

In this situation it becomes much swollen and banded with colours, and produces a large number of ecaudate cercariae.

The cercaria are directly infective to the definitive hosts.

The cercaria swims freely for a time and either encysts directly on grass or weeds or it enters a second host which may be another mollusc, an insect, crustacean or fish, and then encysts.

The further development of the cercaria is dependent on the weed or animal in which it lies being eaten by the final host which is usually a predaceous fish or one of the higher vertebrates.

The cercarial tegument has an outer lipid bilayer which appears as a trilaminate layer in EM, and is covered with a glycocalyx.

The number of cercariae produced by the pullulating rediae in a single water-snail is immense, and as they are emitted at a given period or a few successive periods, the snail at these times appears enclosed in a cloud of whitish flocculent matter.

By a process of infolding, the thicker end is partially invaginated, the middle portion or " hind-body " and the organism may now present a superficial likeness to a cercaria.