state the characteristic features of nematode
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Characteristics of Phylum Nematoda. Nematodes are characterized by their long tube-like appearance that lacks a visually distinct head or tail. ... Roundworms have a complete digestive tract with a mouth at the anterior (head) end and an anus at the posterior (tail) end.
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Phylum Nematoda are un-segmented vermiform animals with anterior lateral chemosensory organs or amphids and with a persistent blastocoel or pseudocoelom; dorsal and ventral nerve cords in epidermis and excretory system of renette cells or tubules.
General Characteristic Features of Phylum Nematoda:
1. Body of Phylum Nematoda is un-segmented, bilaterally symmetrical, elongated and tapering at both ends.
2. Triploblastic animals with perivisceral cavity is more extensive than that of Platyhelminthes.
3. Body of of Phylum Nematoda is generally covered with thick, flexible multi-layered collagenous cuticle and often bears cuticular setae (hairs), spines or annulations.
4. Cuticle moulted periodically.
5. Epidermis or hypodermis syncytial; i.e., the nuclei are not separated from each other by cell membranes.
6. Only longitudinal body-wall muscles; no circular body-wall muscles.
7. Body cavity of of Phylum Nematoda is pseudocoel filled with parenchyma in most cases.
8. Alimentary canal provided with distinct mouth and anus (complete digestive tract). Muscular pharynx and the inner surface of the gut usually not lined by cilia. Extracellular digestion.
9. Mouth of of Phylum Nematoda is surrounded by six lips.
10. Blood vascular system and respiratory system are absent in of Phylum Nematoda.
11. Haemoglobin sometimes present in the pseudocoelomic fluid.
12. Excretory system without nephridia and flame cells. In the class Adenophorea glandular renette cells with a duct or in the class Secernentea excretory canal system without flame cells act as excretory system.
13. Dorsal and ventral nerve cords in the epidermis.
14. Chemosensory organs are small cuticular projections called amphids which are situated on the lips, derived from cilia and opening to the exterior through a small pore, and lined with modified non-motile cilia called sensillae.
15. Sexes of of Phylum Nematoda are separate (gonochoristic).
16. Tubular gonads are present in of Phylum Nematoda.
17. Amoeboid sperm cells.
18. Fertilization is internal in of Phylum Nematoda.
19. Determinate cleavage (mosaic).
20. of Phylum Nematodaare eutelic animals.
21. Generally complex life history.
22. They are free-living or phytoparasitic or zooparasitic.
General Characteristic Features of Phylum Nematoda:
1. Body of Phylum Nematoda is un-segmented, bilaterally symmetrical, elongated and tapering at both ends.
2. Triploblastic animals with perivisceral cavity is more extensive than that of Platyhelminthes.
3. Body of of Phylum Nematoda is generally covered with thick, flexible multi-layered collagenous cuticle and often bears cuticular setae (hairs), spines or annulations.
4. Cuticle moulted periodically.
5. Epidermis or hypodermis syncytial; i.e., the nuclei are not separated from each other by cell membranes.
6. Only longitudinal body-wall muscles; no circular body-wall muscles.
7. Body cavity of of Phylum Nematoda is pseudocoel filled with parenchyma in most cases.
8. Alimentary canal provided with distinct mouth and anus (complete digestive tract). Muscular pharynx and the inner surface of the gut usually not lined by cilia. Extracellular digestion.
9. Mouth of of Phylum Nematoda is surrounded by six lips.
10. Blood vascular system and respiratory system are absent in of Phylum Nematoda.
11. Haemoglobin sometimes present in the pseudocoelomic fluid.
12. Excretory system without nephridia and flame cells. In the class Adenophorea glandular renette cells with a duct or in the class Secernentea excretory canal system without flame cells act as excretory system.
13. Dorsal and ventral nerve cords in the epidermis.
14. Chemosensory organs are small cuticular projections called amphids which are situated on the lips, derived from cilia and opening to the exterior through a small pore, and lined with modified non-motile cilia called sensillae.
15. Sexes of of Phylum Nematoda are separate (gonochoristic).
16. Tubular gonads are present in of Phylum Nematoda.
17. Amoeboid sperm cells.
18. Fertilization is internal in of Phylum Nematoda.
19. Determinate cleavage (mosaic).
20. of Phylum Nematodaare eutelic animals.
21. Generally complex life history.
22. They are free-living or phytoparasitic or zooparasitic.
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