Master Notes on Cnidarians:- 1. Protohydra 2. Halistemma 3. Physalia 4. Porpita 5. Velella 6. Diphyes. Cnidarian # 1. Protohydra: Protohydra (Fig. 12.29A) is a peculiar hydra of 3 mm in length. It lacks the usual tentacles. It is available along the shores of Great Britain and northern part of Europe. Protohydra feeds on nematodes and small crustaceans and propagates [...]
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 Corals:- 1. Definition of Corals 2. Structure of Coral 3. Types 4. Formation. Definition of Corals: The hard external skeleton of certain solitary and colonial marine anthozoan cnidarians; composed chiefly calcium carbonate. Structure of Coral: Coral is secreted by some coral forming actinozoa. The skeleton of a solitary polyp is known as the [...]