How are animal specimens made?
1. Preparation of dried animal specimens [1] Preparation method of insect adult specimens Before making insect specimens, the insects should be put to death. The simple implementation method is to smoke with ether or inject formaldehyde into the body. (1) Needle feeding method This is the simplest and most practical method for fixing insects. Insert insects on the needle board with an insect needle to shape them, and dry them to make specimens. Needle plate is made of loose thin plate. The position of the needle varies with the size and species of insects. Then use tweezers to correct the posture of tentacles, feet and wings and fix them with pins respectively. (2) The winged method should be adopted when making adults such as Lepidoptera and Dragonfly. A. Manufacture of simple paving board: cut the plastic foam board with a thickness of more than 2cm into squares with a width of about 10cm. According to the collected insect body size, dig a groove in the middle of the board so that the insect's chest and abdomen are just placed inside. B don't touch the front of the wing when taking moths and butterflies from the wing slot to prevent scales from falling off. Insert an insect needle or needle vertically into the middle of the insect's chest and back, leaving about 0.7cm above, and then insert the needle into the middle of the slot of the wing display board, so that the head, chest and abdomen are just in the slot, and the wing root is the same height as the upper surface of the wing display board. Gently clamp the butterfly wings with tweezers to spread them to the left and right, and gently stretch the front wings to the front of the head so that the rear edge of the front wings is perpendicular to the edge of the wings on the same side. At this time, press the front wing with a set of paper strips, and insert a pin near the leading edge and trailing edge of the wing to fix the front wing (be careful not to insert the pin on the wing). After the front wing is fixed, clamp the rear wing with tweezers, move it slowly so that the front edge of the rear wing is slightly parallel to the rear edge of the front wing, fix it with paper strips, and dry it in a cool place in a ventilated place. Some insects, such as moths (including pupae), mantises, locusts and so on. There is a swollen and full belly, and the specimens made are easy to mildew and deteriorate after drying and shrinking. You can cut a hole in the abdomen of these insects with scissors, take out the internal organs with tweezers, wipe the inner wall with cotton wool, knead the cotton wool into a cotton ball similar to the abdomen, dip it in camphor powder, stuff it into the abdomen, and sew the incision on the abdominal wall with tweezers. Then put the insect on the needle board, insert the insect needle into the chest, pose the tentacles and feet, and dry. Dragonflies have a long abdomen and a thin abdominal wall, which are easy to break after being made into specimens. Therefore, fine bamboo filaments should be inserted from the tail tip of the dragonfly, through the abdomen and chest, all the way to the head, and then cut off the bamboo filaments exposed from the tail tip. The dragonfly treated in this way is straight and hard. (3) Sticking method Small insects such as mosquitoes, houseflies, aphids, etc. No needles. A small amount of polyvinyl acetate glue can be coated on the tip of the insect needle and sporadically on the center of the table paper. Hold the insect gently with tweezers, stick it on the table paper, and arrange the tentacles, feet and wings with needles. Then use insect needles to fix insects and table paper together on the board. After making the specimen, sprinkle camphor powder on the edge of the table paper and dry it in the shade. [2] Preparation of dry specimens of invertebrates (1) After the dried starfish of starfish specimens are collected from the sea, they should be put in a bucket filled with seawater. First, anesthesia is performed with laxative (MgSO4), which is usually not put in water. Anesthetized starfish were killed in formalin. 1-2 hours later, take it out of the formalin, make it face up, expose it to the sun for 4-5 hours, and then turn it over to bask in the back after it is slightly dry. Do this for a few days until it is completely dry, or dry it in an infrared oven. Sprinkle some camphor powder on the bottom of the glass carton, then spread cotton wool, add dried starfish, put a label next to the carton and cover it. (2) Drying of Shell Samples After collecting mollusk materials such as Gastropoda and Cladosporium, put them in boiling water for about 6 minutes. Take out the material and use a needle or crochet to pull out the meat from the shell. If some meat remains, soak the material in boiling water for 5-6 minutes, and vibrate by hand to make the remaining meat flow out of the shell with water. If the leftover meat can't come out again, change the water and soak it several times. To make the shell surface shiny, you can soak the shell in warm 4-5% dilute hydrochloric acid for a few minutes, then take it out, rinse it with water and apply a layer of light wax. Freshwater shells can't use the above methods, and the materials should be soaked in 3-5% potassium hydroxide solution for more than ten minutes. Finally, paste the serial number and make up the instructions. (3) drying crab specimens: firstly, dig the crab meat, separate the head from the breastplate, dig the meat in the body with a flat wire, and then dig the meat that pinches the feet. Then, lead out the wire No. 18 or No.20 is inserted into the crab's pliers and tripod. One end of the wire is led into the tip of the limbs, and the other end is concentrated in the chest and abdomen. Then, two wires are inserted from the abdomen as a support frame and fixed on the chassis. Put the crab with lead wire on the dissecting board and fix the foot with a pin. Then paint formalin with a brush, and inject a small amount of 16% formaldehyde between limbs with a syringe for anticorrosion. Dry the specimen in the shade, and finally stick it on the breastplate with milky white, and then color the specimen with oil paint according to the body color. 2. Production of animal soaked specimens [1] The whole production process of soaked specimens is: material selection, execution, posing, antiseptic fixation, bottling and preservation, numbering, recording and labeling. This method is simple and feasible. (1) Materials should be medium-sized animals. Try to choose fresh fish and keep the fins and scales intact. Living amphibians and reptiles should be put in a closed container, and cotton balls soaked in ether should be put in to make them anesthetized to death. (2) Pose until the animal is anesthetized and taken out after death. Wash the mucus on the body surface with clear water, then number it, register the record and fasten the label. Then inject proper amount of formalin into abdominal cavity to fix internal organs. The fish unfolds the dorsal fin, pectoral fin and caudal fin properly, and clamps the plastic sheet or thick paper with the fish fin with a paper clip to unfold it in a living state. Amphibians live in a crawling posture. Open your fingers and toes. When finishing amphibians, first put a ball of absorbent cotton in your mouth with tweezers to make it open so that you can observe your teeth. Roll its body into a spiral shape so that its head is on the floor, or fold it into an "S" shape. The limbs of turtles and lizards should be fixed on wax boards with pins. (3) Fixing preservation: soaking and fixing the internal tissues with formalin. After fixation, fix the specimen on the glass with white thread, put it in a suitable specimen bottle, and soak it in formalin for preservation. [2] The key of animal specimen soaking system is the anatomy and treatment of soaking system. Here, taking the soaking system of rabbit reproductive system as an example, the specific production method is introduced. (1) Adult female and male rabbits were selected, and their carotid arteries were cut and bled to death. (2) Anatomy: Rinse the skinned rabbit, put it on a dissecting dish or plate, and cut open the abdomen. Removing pelvic muscles can better expose pubic bone and ischium. The pubic bone and ischium were cut off at the center of the whole length with bone forceps, and the reproductive system was removed and excreted. Do not discard the remaining head and chest materials after taking them out. You can make respiratory specimens. Female rabbit's reproductive system: a pair of ovaries, flat and oval, suspended on both sides of the back of abdominal cavity through special mesentery. The fallopian tubes are a pair of curved tubules hanging on the mesentery, and the front ends are funnel-shaped and communicate with the abdominal cavity. The posterior end of each fallopian tube expands into a uterus. The left and right uterus merge into vagina. Genital foramen is a wide longitudinal fissure with labia as the circumference, and a small amount of body wall around it needs to be removed to take out all the excretory system. Male rabbit's reproductive system: a pair of testicles, white oval, with epididymis on the back of each testicle. The vas deferens is a slender tube, which starts from the testis, enters the abdominal cavity through the inguinal canal, opens in the urethra and enters the penis behind the pubic symphysis. There are seminal vesicles and prostate on the back of urethra. The penis consists of two sponges. By cutting off the body wall around the cavernous body, all the excretory systems can be removed. (3) Set the width of the glass inserted into the specimen bottle, and arrange the female and male reproductive systems taken out on the anatomical plate in turn. Soak in formalin solution. (4) Trimming and preservation: wash the specimen with water, put it on an anatomical plate, and cut off the redundant tissue. Fix it on the glass and bottle, as before.