The following points highlight the two main types of polymorphic variabilities in Siphonophora. 1. Modifications of the Polyp: A. Gastrozooids or Trophozooids or Nutritive Zooids: Characters: 1. It is like a typical polyp (Fig. 12.34A,B). 2. Each gastrozooid is a cylindrical and funnel-shaped body with a large mouth. 3. Presence of a well-formed coelenteron. 4. A single long contractile and [...]
In this article we will discuss about Hydra:- 1. Habit and Habitat of Hydra 2. Structure of Hydra 3. Structure and Function of the Different Cellular Units 4. Locomotion 5. Nutrition 6. Respiration and Excretion 7. Reproduction 8. Life History. Contents: Habit and Habitat of Hydra Structure of Hydra Structure and Function of the Different Cellular Units of Hydra Locomotion [...]
In this article we will discuss about the interrelationships between the different classes of phylum Cnidaria. Class Hydrozoa represents the most primitive forms amongst the Cnidarians. The lowest hydrozoan form is exhibited by Hydra and the hydrula stage of some Hydrozoa. The relationship between Hydrozoa and Scyphozoa is not very clear. In spite of this, it can be suggested that [...]