In this article we will discuss about the spicules and gemmule of sponge. Spicules of Sponge: 1. The spicules are structures which form the supporting skeleton in sponges. 2. They may be either calcareous or silicious in nature. 3. They may be either monaxon (having one ray) triaxon (having 3 rays) or tetraxon (having 4 rays). 4. Some times they [...]
In this article we will discuss about the Tentaculocyst of Aurelia with the help of a diagram. 1. It is the slide of tentaculocyst of Aurelia which is also known as rhopallium statocyst. 2. It is a club-shaped structure and is located between the two marginal lappets. It is covered by the hood (the bell margin) on outer side. 3. [...]
In this article we will discuss about the anatomy of sycon. L.S. of Sycon: Fig. 93. L.S SYCON 1. Body wall is diploblastic with an outer ectodermal or dermal epithelial layer and inner gastric epithelial layer or endoderm. 2. Non-cellular mesenchyme layer with interspersed monaxon and triaxon spicules is present in between the two layers. 3. The dermal epithelium is [...]