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polychaeta's Usage Examples:

Finally, there are certain Polychaeta, e.g.

It has been asserted (and denied) that the cellular rod which is known as the "Heart-body" (Herzkorper), and is to be found in the dorsal vessel of many Oligochaeta and Polychaeta, is formed of cells which are continuous with the chloragogen cells, thus implying the existence of apertures of communication with the coelom.

The plasma is coloured red by haemoglobin: it is sometimes (in Sabella and a few other Polychaeta) green, which tint is due to another respiratory pigment.

With a few exceptions among the Polychaeta the vascular system is always present among the Chaetopoda, and always consists of a system of vessels with definite walls, which rarely communicate with the coelom.

Thus, among the Oligochaeta there are often a series of dorsal pores, or a single head pore, present also among the Polychaeta (in Ammochares).

This is the typical arrangement, which is exhibited in the majority of the Polychaeta and Oligochaeta; in these the successive chambers of the coelom are separated by the intersegmental septa, sheets of muscle fibres extending from the body wall to the gut and thus forming partitions across the body.

On the other hand, in certain Polychaeta the bundles of setae are so extensive that they nearly form a complete circle surrounding the body; and in the Oligochaet genus Perichaeta (=Pheretima), and some allies, there is actually a complete circle of setae in each segment broken only by minute gaps, one dorsal, the other ventral.

They are disposed in two groups on either side, corresponding in the Polychaeta to the parapodia; the two bundles are commonly reduced among the earthworms to two pairs of setae or even to a single seta.

The setae are organs of locomotion, though their large size and occasionally jagged edges in some of the Polychaeta suggest an aggressive function.

Where locomotive appendages (the parapodia of the Polychaeta) exist, they are never jointed, as always in the Arthropoda; nor are they modified anteriorly to form jaws, as in that group.

polychaeta's Meaning':

marine annelid worms

Synonyms:

class Polychaeta, lug, lugworm, class, family Terebellidae, lobworm, polychete worm, polychaete, polychete, Annelida, polychaete worm, Terebellidae, phylum Annelida,

Antonyms:

unstuff, unclog, inelegance,