The following points highlight the two main types of meiotic division. The types are: 1. The First Meiotic Division or Heterotypic Division 2. The Second Meiotic Division or Homeoptypic Division. Type # 1. The First Meiotic Division or Heterotypic Division: i. First Prophase Stage: This stage is divided into following stages: (a) Leptotene sub stage: The slide shows the first [...]
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 [...]
The below mentioned article provides a diagram of amphiblastula (larva). 1. It is a free swimming larval stage of Sycon and many other calcareous sponges. 2. The body is some what ovoid in form and is comprised of an anterior half of small flagellated micromere cells and a posterior half of large non-flagellated macromere cells. 3. It encloses a small [...]