annelids. The clitellum, a saddle-shaped thickening of the body wall, is present at sexual maturity. ... because both groups possess a clitellum. The Archiannelida and Myzostomida treated as polychaete orders in the classification system above have been considered as separate classes in the past.

Is clitellum present in annelids?

The clitellum is part of the reproductive system of clitellates, a subgroup of annelids which contains oligochaetes (earthworms) and hirudineans (leeches). ... Occasionally, living segments of the worm will be shed with the clitellum.

Do all earthworms have a clitellum?

The clitellum is only found on adult worms. Young or juvenile worms do not have a clitellum. The clitellum of each species of earthworm has a distinct colour, size, and shape. Another key structure found on the clitellum is the tubercula pubertatis.

What is the clitellum function?

The clitellum is a thick, saddle-like ring found in the epidermis (skin) of the worm, usually with a light-coloured pigment. To form a cocoon for its eggs, the clitellum secretes a viscous fluid. The main function of clitellum is cocoon formation.

Do male earthworms have clitellum?

The earthworms each have two male openings and two sperm receptacles, which take in the sperm from another mate. The earthworms have a pair of ovaries that produce eggs. The clitellum will form a slime tube around it, which will fill with an albuminous fluid.

Sexual reproduction in Earthworm English medium |Prof Masood fuzail |BShons zoology lecture

24 related questions found

Why do all earthworms have a clitellum?

Explanation: The clitellum is a thickened glandular and non segmented section of the body wall near the head of the earthworm that secretes a viscid sac in which the eggs are deposited. The clitellum is part of the reproductive system of earthworm. It also secretes a viscous fluid to form a cocoon for it's eggs.

Do leeches have clitellum?

As hermaphrodites, leeches have both male and female sex organs. Like the earthworms they also have a clitellum, a region of thickened skin which is only obvious during the reproductive period.

What is the function of the clitellum quizlet?

What is the function of the clitellum, the only organ visible externally on earthworms? It secretes mucus that is important in reproduction. The worm alternates between extension and pulling the rest of its body after the extension.

What is the purpose of excretory openings in earthworms?

Excretory System of Earthworms

Earthworms use diffusion to excrete carbon dioxide through their skin. For the nitrogenous wastes, the excretory system of earthworms contains specialized organs known as nephridia.

Do earthworms have eyes?

No, not really. Instead, they have cells called receptors that can sense whether it's light or dark. This allows worms to tell if they're underground or above ground.

What is the bump on an earthworm?

The bump is the clitellum, the saddle shaped swollen area 1/3 of the way back containing the gland cells which secrete a slimy material (mucus) to form the cocoon which will hold the worm embryos.

Do worms have eyes and noses?

SIGHT Earthworms don't have eyes like we do, they have organs that help them sense whether they are in the light or in the dark. SMELL Earthworms don't have a sense of smell or a nose to breathe with like we do, but they do have to breathe! Earthworms breathe by absorbing oxygen through their skin.

Which of the following animals has a clitellum?

Correct Option: C. A clitellum is part of a of the reproductive system of clitellates, a subgroup of annelids which contains oligochaetes (earthworms) and hirudineans (leeches). The clitellum is a thick, saddle-like, ring found in the epidermis (skin) of the worm, usually with a light colored pigment.

In which segment clitellum is present?

Clitellum. The clitellum is a thickened glandular and non-segmented section of the body wall near the head in earthworms and leeches, that secretes a viscid sac in which the eggs are deposited. It is located near the anterior end of the body (around the 14th, 15th and 16th segments).

Are annelids Monoecious or dioecious?

Annelids may be either monoecious with permanent gonads (as in earthworms and leeches) or dioecious with temporary or seasonal gonads that develop (as in polychaetes). However, cross-fertilization is preferred in hermaphroditic animals.

What are the excretory organs of annelids called?

Earthworms (annelids) have slightly more evolved excretory structures called nephridia, illustrated in Figure 2b. A pair of nephridia is present on each segment of the earthworm. They are similar to flame cells in that they have a tubule with cilia.

How do annelids excrete waste?

Excretion. The annelid excretory system is made up of long tubular organs called nephridia. ... The nephridia each have an opening called a nephrostome that takes in body fluids from the coelom, and an exit pore in the body wall called the nephridiopore releases waste from the worm.

Which one of the following is not an excretory activity?

Answer: Carbon dioxide is formed as a waste product of respiration and hence is not exactly an excretory activity. B) ... D) Removal of ammonia waste in the form of urea (in humans) is called excretion. So the correct answer is 'Giving out carbon dioxide'.

What is the clitellum quizlet?

Clitellum: series of anterior segments enclosed in thick glandular epidermis; encompasses females gonopores and secretes mucus. Hermaphrodites, zygotes develop in a coccon and emerge and juveniles, direct development.

What feature of the intestine increases its surface area and hence an earthworm's ability to absorb nutrients?

Instead of being coiled like a mammalian intestine, in an earthworm's intestine a large mid-dorsal, tongue-like fold is present, called typhlosole which increases surface area to increase nutrient absorption by having many folds running along its length.

Do you see any differences between the musculature of the crop and that of the gizzard?

The crop's walls are very thin. The gizzard's walls are very thick. The gizzard grinds food.

Are leeches Monoecious or dioecious?

Leeches (Hirudinea), also monoecious, have one pair of ovaries and a segmentally arranged series of testes with duct systems basically similar to those of earthworms.

Do leeches have eyes?

Leeches have simple eyes which detect light and dark, rough shapes and motion. Colour and pattern vary greatly from species to species, but most tend to be darker coloured with blotches, spots or stripes.

What stores spermatozoa in leech?

Answer: Explanation: Developing sperm are frequently stored in seminal vesicles before transfer to female receptacles. Sperm ducts lead from the seminal vesicles to male pores located one or more segments behind the testes.