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 [...]
In this article we will discuss about Aurelia:- 1. Structure of Aurelia 2. Sense Organs of Aurelia 3. Histology 4. Life History. Structure of Aurelia: Adult Aurelia represents medusoid stage. It has the typical form of a medusa (Fig. 12.18). But the concave and convex sides of the umbrella are more pronounced. The edge of the umbrella is provided with [...]
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 [...]