Question

Pseudometamerism occurs in
a. Turbellaria
b. Trematoda
c. Cestode
d. All of the above

Answer 1

Hint: The process of segmenting one’s body into somites or metameres is called metamerism. Pseudo metamerism occurs in an animal where the segments are independent of the other. They contain a complete set of organs that have no assembly with organs in other segments. Also, all segments are unified into a single functional unit.

Complete answer:
> Tubellari is one of the traditional sub- divisions of the flatworms. Since, there is a lack of respiratory a circulatory system.

> Trematoda are flattened oval or worm-like animals. The mouth located the center of animal pumping a muscular.

> Cestode: It is a tapeworm can be found in the host of gastrointestinal tract.
(a) The Pseudo metamerism occurs in all the above organisms. The metamerism is observed in organisms like tapeworms and flatworms.
(b) In detail we can say that such type of metamerism occurs when there is a presence of segmentation in the body by the segmentation of the ectoderm.
(c) Such type of metamerism is called Pseudo metamerism or stabilization. We can say that the body of the organisms contains a number of segments or proglottids, however, vary in different individuals of the same types.
(d) Thus, we can say that the tapeworms of class cestoda, flatworms of class Turbellaria, and flukes of class Trematoda have this type of metamerism.

Hence, the correct answer is option (C).

Note: The proglottids is the name given to the many similar units on the body of tapeworms. These proglottids are said to contain packages of eggs that are regularly shed into the environment. They release these eggs to infect other organisms present in the same environment. Thus, the existence of proglottids is very essential in earthworms.