Failed the college entrance examination and went home to fish

Chapter 144 142. Jellyfish
A man rested on the boat for a while, ate and drank a little.After watching the jellyfish for a while, after discussing for a while, I decided to continue and catch the jellyfish.

"Okay, okay, don't rest, let's go first, let's say it again, after the jellyfish comes back this time, we will have dinner directly."

Could it be that Luo Jinshuo can have dinner directly after finding it this time?Everyone jumped up excitedly.

"Then we must have dinner. Needless to say, let's go and come back to have dinner immediately. We decided to have dinner so happily."

"Okay, okay, I know that you are the most active. You don't work hard, and you are the most active in doing things. Okay, let's apply mineral water first. After spending time, we will go down to grab some fruit and pack it. After that, we can go to have dinner. gone."

After they finished speaking, they put on their wetsuits and jumped in to dive.

After a while, I came directly to the place just now. Looking around, there were indeed many jellyfish.

Here I will introduce you to jellyfish and help you popularize knowledge in this area.

Different jellyfish have different forms, and there are about 250 species in the world.The body of jellyfish is more than 95% water, and the rest is composed of protein and lipid, so the body of jellyfish is transparent because of the water in the body. They have no heart, blood, gills and bones.Common jellyfish umbrellas are not very large, only 20-30 cm long.

Some jellyfish not only change colors, but also glow in the water, some with faint light green or blue-purple light, and some with rainbow-like halo, when they swim in the sea, they become a Glowing colored balls.The jellyfish's light depends on a wonderful protein called equimin, which emits a strong blue light when mixed with calcium ions.The greater the amount of equamine in the jellyfish, the stronger the light. Each jellyfish contains only 50 micrograms on average.

Jellyfish have three germ layers, the outermost layer is the epidermis, and the innermost layer is the gastric cortex. The gastric cortex forms a simple body cavity with only one opening, which has the functions of mouth and excretion. It is the middle glue layer.Taking the jellyfish as an example, the body of jellyfish has several structures.

Formed by the gastric cortex, it is the digestive system of jellyfish. There is a gastric aqueduct system in the stomach cavity, and there are many tentacle-like gastric filaments, and there are stinging cells on the gastric filaments, which can anesthetize the bait eaten, and then release digestive juice. for digestion.The gonads are also located on the wall of the gastric cavity and also originate from the gastric cortex.

There are eight sensory sticks on the edge of the jellyfish's wings, and there is a balance cell, ommatidium and two sensory sockets inside, which are used to balance the body and touch in the water. It can be said that it is the sensory organ of the jellyfish.

There are many small tentacles on the edge of the jellyfish's wings. The front ends of the tentacles have cnidocytes, which can catch plankton and attack enemies.

Cnidocyte: It is one of the cells at the front of the tentacles. Coelenterates are also called cnidocytes, which refers to this, so jellyfish are more or less toxic.Cnidocytes are a fluid-filled sac with a hollow, wound tube inside. The surface of the cnidocytes has a small needle called a cynidactylyte, which acts like a switch. , these tubes containing venom paralyze the stinged creature.

Mouth arm: The same number of arms extending from the center of the jellyfish wing as there are stomach pouches.There are also many stinging cells on the wrist, which can not only capture prey, but also send food into the mouth.There is a nurse sac at the bottom of the mouth arm, and the tectus larvae developed from fertilized eggs will attach to the nurse sac.

Mouthparts: Located at the base of the wrist of the mouth, leading directly to the gastric cavity.In addition to being eaten into food, it also has the function of excretion.

Radiation tube: The tube extending radially from the stomach cavity to the jellyfish wing, which can circulate digested nutrients and oxygen in the body, and has a blood vessel-like function.

Through the above introduction, we can know that the body structure of jellyfish is much simpler than that of humans.

In other words, his biological level is much lower than that of human beings, and he even has no brains.

After a while, Ye Kai and the others discovered another very beautiful jellyfish, which is the purple sea thorn jellyfish.

The purple sea thorn jellyfish is also known as the colorful golden jellyfish. The outer umbrella has purple strips and purple tentacles. The diameter of the umbrella can reach more than 30cm.Jellyfish are invertebrates belonging to the coelenterate phylum.The purple sea thorn jellyfish has four oral tentacles and eight marginal tentacles, and the purple stripes on its back are very eye-catching.The purple sea thorn jellyfish usually lives with a hermit crab.

This jellyfish video is called a special kind of jellyfish, and they live in symbiosis with a kind of hermit crab.

The purple sea thorn jellyfish is an important large plankton in the ocean.Jellyfish are short-lived, averaging only a few months.Jellyfish are invertebrates belonging to the coelenterate phylum.There are more than [-] species of jellyfish in the world's oceans, and they are distributed in waters all over the world.

The longest-lived creature is also a jellyfish.

The lighthouse jellyfish is a small jellyfish with a bell-shaped body and a red digestive system that looks like a lighthouse, hence the name. It mostly lives in tropical seas, mainly in the Caribbean, Spain, Italy and Japan. It is also distributed offshore.

The lighthouse jellyfish is a small jellyfish.The body is bell-shaped, with a diameter of about 4-5 mm. The body is transparent, and the red digestive system can be seen. It looks like a lighthouse, hence the name.The diameter and height of the umbrella-shaped body are basically equal.The protruding side is called the outer umbrella surface, and the concave side is called the lower umbrella surface. In the center of the lower umbrella surface, there is a drooping tube called the vertical lip. The free end of the vertical lip is the mouth. There is a circle of tentacles on the edge of the umbrella. The edge of the jellyfish's umbrella protrudes inwards with a narrow membranous structure called the limbal membrane, which is a characteristic of the hydrozoan jellyfish.

The body wall structure is composed of two layers of epithelial muscle cells sandwiched by a middle glue layer.Four radiation tubes protrude from the gastric sac to the edge of the umbrella, and are connected with the ring tube parallel to the edge of the umbrella.Sensory organs such as eye-spots or balance sacs are located on the fringe or at the base of the tentacles.

The stomach of the lighthouse jellyfish is huge and bright red, with a cross-shaped cross-section.

Lighthouse jellyfish mostly live in tropical waters.It is carnivorous and feeds on plankton, small crustaceans, polychaetes and even small fish.

Due to the mechanical and chemical stimuli of the food, the polyps elongate their tentacles and release nematocysts to entangle, paralyze and poison the prey, and then send the food into the mouth.

The mucus secreted by the gland cells in the mouth area is conducive to the swallowing of food. After the food enters the gastric cavity, the gland cells in the gastric layer begin to secrete protease, which decomposes and digests the food to form many polypeptides. to be mixed and driven.After this extracellular digestion, the intracellular digestion process begins. The pseudopodia of the nutrient muscle cells engulf food particles, forming a large number of food bubbles in the cells. After acidic and alkaline chemical processes, the nutrients are diffused from the cells. The effect is delivered to the whole body.

(End of this chapter)