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 [...]
In this article we will discuss about the histological organisation of Cnidarians. 1. Ectoderm: In most cases it is distinctly cellular. Presence of ciliated ectoderm in larval cnidarians is usually seen. The cellular ectoderm is mainly composed of the supporting cells, called the Epitheliomuscular cells. They are usually cuboidal or columnar in shape. They may be thin and flattened (exumbrellar [...]