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Learn about the comparison between Aurela and Urticina.
Comparison # Aurelia:
1. Aurelia is elongated tube-like body with narrow proximal end differentiated into stalk for attachment.
2. Aurelia is about 1.5 cm in height.
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3. Distal tentacle:
16 solid tentacles developed in regular order (4 per-radial, 4 inter-radial and 8 ad-radial tentacles).
4. Manubrium is present in Aurelia.
5. Mouth of Aurelia is square in outline and is placed in the manubrium.
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6. Four inter-radial septal funnels are present in Aurelia which sink into gastric ridges.
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7. True mesenteries are absent and 4 gastric ridges are present which can be compared with the mesenteries of Urticina.
8. Mesenteric filaments are absent in Aurelia.
9. Enteric system is simple in organisation.
10. Reproduction in Aurelia is by budding and transverse fission or strobilation.
Comparison # Urticina:
1. Urticina is cylindrical body with a proximal broad base for attachment, an upright column and a distal horizontal disc, called peristome.
2. Diameter of the body may slightly exceed height and is about 7.5 cm. across.
3. Distal tentacle:
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Numerous short, hollow and conical tentacles are arranged in 5 circlets.
4. Manubrium is absent in Urticina.
5. Mouth of Urticina is slit-like—situated in the middle of the peristome.
6. Septal funnels are absent in Urticina.
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7. The stomodaeum and the body wall are connected by numerous radiating partitions, called mesenteries. The mesenteries are of three types—primaries, secondaries and tertiaries.
8. The free edge of each mesentery below the gullet produces twisted cord, called mesenteric filaments, which may in turn produce slender thread-like acontia.
9. Enteric system in Urticina is very much complicated and is divisible into stomodaeum, stomach and radially arranged inter-mesenteric chambers produced by the primary mesenteries.
10. Urticina develops gonads in the mesenteries and gonads are endodermal in origin.
