rn(ii) Very well developed parapodia with acicula and setae. rn(iii) Head with a distinct prostomium bearing sensory constructions and peristomium with mouth.

rn(iv) Pharynx ordinarily protrusible with chitinous jaws and teeth. rn(v) Branchiae, when present, not found in the anterior end. Pelagic, crawling, burrowing and tube-dwelling forms.

It features twenty households. Some of the fami­lies with examples are:Family Aphroditidae (e. g.

Precisely what is a descriptive essay?

, Aphrodita = Aphrodite)-sea mouse. Family Phyllodocidae (e. g. , Phyllodoce).

Family Polynoidae (e. g.

, Polynoe)-scale worms. Family Syllidae (e. g.

, Syllis, Autolytus). Family Nereididae (e. g. , Dendronereis, Nereis, Platynereis)-ragworms. Family Glyceridae (e.

g. , Glycera)- tongue worm.

Family Eunicidae (e. g. , Eunice, Marphysa, Palola)Family Myzostomidae (e. g. , Myzostonw- commensals and parasites of echinoderms essentially on crinoids). rn(B) Team II. Polychaeta Sedentaria (Sedentary polychaetes) [L.

sedentarius = sitting down]:rn(i) Overall body of two or more areas with dissimilar segments and parapodia. rn(ii) Lowered parapodia without having acicula. rn(iii) Head inadequately made and offered with palps and tentacles,rn(iv) Prostomium without sensory ap­pendages.

rn(v) Pharynx normally non-protrusible, and without the need of jaws and tooth. rn(vi) Branchiae, when current-generally existing in the anterior finish. Sedentary, burrowing and tubicolous worms, feed in detritus or plank­ton. Family Chaetopteridae (e. g. , Chaetopterus, Mesochaetopterus, Siphonochaetop- terus)-paddle https://www.reddit.com/r/PaperHub/comments/x9r6o1/paper_help/ worms. Family Arenicolidae (e. g. , Arenicola)- lugworms. Family Terebellidae (e. g. , Terebella, Amphitrite, Polymnia). Family Sabellidae (e. g. , Sabella, Myxicola, Fabricia, Potamilla)-fanworms. Family Serpulidae (e. g. , Serpula, Spirorbis, Pomatoceros, Spirobranchus)- fanworms. Archiannelida (Gk. archi – first):rn(i) Heterogenous insignificant group. rn(ii) Entire body compact, very simple, elongated and vermiform. rn(iii) Simplified structure. rn(iv) External segmentations indistinct but interior segmentation current. rn(v) Setae and parapodia usually absent. rn(vi) Head bears perception organs,rn(vii) Unisexual or hermaphrodite. rn(viii) Blood vascular system very simple or lack­ing. rn(ix) Larva trochophore. rn(x) Maritime, brackish or freshwater spe­cies. Nerilla, Troglochaetus, Poly­gordius, Protodrilus, Dinophilus, Trilobodrilus. Previously some zoologists deal with ‘Archiannelida’ as an appendix to the class polychaeta but Knox (1972) has addressed it as a sepa­rate course. Barnes (1980, ’87) re­ported that Archiannelida is a team which contains most of the degenerate polychaetes. Most of the new authors are of view that the archiannelids are the specialized aberrant associates of the annelids and represent as family members of the polychaeta. The position given to the archiannelids as the course is an synthetic just one. Class 2. Oligochaeta (Gk. Oligos = number of L. chaetae = bristles):1. Streamlined physique with effectively-made segmentation and a basic prostomium without the need of sensory ap­pendages, these types of as eyes, and tenta­cles. 2. Head indistinct. 3. Clitellum existing. 4. Parapodia and cirri absent. 5. Setae less dispersed together the human body. rn ) which have correct gills. Gas trade normally takes place by diffusion by way of the moist overall body wall.

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