In this article we will discuss about the General Characters and Classification of Phylum Cnidaria. General Characteristics of Phylum Cnidaria: Some of the important General Characters of Phylum Cnidaria are listed below: 1. Habitat: All are aquatic and are mostly marine, except a few like Hydra, are fresh water. 2. Body Form: Body form varies considerably. Many colonial cnidarians like [...]
In this article we will discuss about the meaning and classification of phylum cnidaria. Meaning of Phylum Cnidaria: The phylum Cnidaria (coel=hollow; enter on—gut) includes the simplest of the cellular animals or xnetazoa. The coelenterate body is a two-layered sac, opening to the exterior by a single aperture called mouth. The mouth is surrounded by a number of tentacles and [...]
The relationship between metagenesis and polymorphism has raised the question—is metagenesis an outcome of polymorphism or has it lead to the emergence of polymorphism? A discussion on the existence of different grades of metagenesis in cnidarians will help us to find a logical answer. Gradations of Metagenesis: Four different forms of life-histories are seen in the cnidarians which exhibit a [...]