Question

explain the types of Ceolomate​

Answer 1

Answer:

There are three types of coelom, such as:

(i) Acoelom,

(ii) Pseudocoelom and

(iii) Coelom or Eucoelom.

 

 ACOELOM:---  It means without a coelom or fluid-filled cavity is absent. The space between the gut and body wall is filled by a kind of densely packed connective tissue derived from both ectoderm and endomesoderm (entomesoderm), called parenchyme. Animals are without a body cavity in triplooblastic animals, called acoelomates and the group is referred to as acoelomata.

Examples:

Gnathostomulida, Platyhelminthes and Nemertea, Gastrotricha, Kinorhyncha.

(ii) Pseudocoelom:It means false cavity. The fluid-filled body cavity lying between the gut and outer body wall musculature and generally formed by persistence of em­bryonic blastocoel is called pseudocoel. The term ‘pseudocoelom’ usually refers to the space which does not develop from embry­onic mesoderm and not lined by coelomic epithelium derived from the mesoderm.

The body cavity is bounded externally by the fibrous processes of the longitudinal muscle cells (mesoderm) and internally by the intes­tine (endoderm).

The pseudocoelomic fluid acts as a hydrostatic skeleton to maintain body shape and circulate nutrients. Animals that contain a pseudocoel are called pseudo- coelmates or pseudocoelomate animals. Pseudocoelomate animals are also referred to as haemocoelomate or blastocoelomate animals (Brusca and Brusca, 2003).

Exam­ples:

Rotifera, Nematoda, Nematomorpha

  (iii) Coelom or Eucoelom:

It is a true coelom lying between the gut and outer body wall musculature and lined by coelomic epithelium derived from the embry­onic mesoderm. It is a mesodermal origin and opens to the exterior through the coelomoducts, e.g., the oviducts and the excretory ducts. The coelomic fluid contains amoeboid cells or amoebocytes. The animals containing such a body cavity or coelom, called coelomates.

Examples:  

   Sipuncula, Echiura, Priapulida, Mollusca,