HydraA genus of freshwater polyps in the family Hydridae, order Hydroida, class HYDROZOA. They are of special interest because of their complex organization and because their adult organization corresponds roughly to the gastrula of higher animals.
PolypsDiscrete abnormal tissue masses that protrude into the lumen of the DIGESTIVE TRACT or the RESPIRATORY TRACT. Polyps can be spheroidal, hemispheroidal, or irregular mound-shaped structures attached to the MUCOUS MEMBRANE of the lumen wall either by a stalk, pedunculus, or by a broad base.
FamilyA social group consisting of parents or parent substitutes and children.
AdultA person having attained full growth or maturity. Adults are of 19 through 44 years of age.
GastrulaThe embryo in the early stage following the blastula, characterized by morphogenetic cell movements, cell differentiation, and the formation of the three germ layers.
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