Tachpleus tridentatus．

Alias: Three-spined horseshoe crab, sea monster.

Taxonomic position Arthrropoda Xiphosura Limulidae Tachypleus of Limulidae.

Chinese horseshoe crab is ladle-shaped, consisting of three parts: head, chest, abdomen and tail sword. It is covered with hard armor, with a rounded back and a sunken abdomen. It is a rare arthropod in warm water offshore.

Horseshoe crab originated in the Devonian of Paleozoic, earlier than dinosaurs and primitive fish. Known as a "living fossil", it has academic research value.

The meat and eggs of horseshoe crab have high nutritional value, are delicious, and taste like crab, which is a favorite dish for people in the southeast coast. As a raw material of medicine, it has many curative effects. According to Jiayou Materia Medica in Song Dynasty, horseshoe crab meat is mainly used for hemorrhoids. Eggs can cure red and glaucoma; Gallbladder is mainly used for treating wind epilepsy and cough for years; Tail burning is mainly used to treat soup wind, bleeding, gynecological collapse, postpartum dysentery and other symptoms; Burning crustaceans to ashes can cure cough and reduce high fever. Up to now, there are still many proven prescriptions of limulus in China. Using horseshoe crab blood to extract the lysate of deformed cells to make a reagent for endotoxin test, which is extremely sensitive, rapid and simple. It only takes 15 minutes to identify meningitis, which greatly shortens the detection time compared with the conventional bacterial culture method, thus attracting the attention of all countries in the world. 1986 Pingtan built a reagent factory, and the product quality reached the standards issued by the Ministry of Health.

Although horseshoe crab originated in ancient times, its development is very slow and its resources are very small. The horseshoe crab production in Fujian ranks first in China, with Pingtan, Xiamen and other coastal areas as the main producing areas.

The horseshoe crab lives on the sandy seabed, crouches in the daytime and comes out at night. Most of the time, it lives in benthic seclusion. Usually, small individuals live on the beach, and with the growth of age, large individuals gradually move to the shallow sea. The horseshoe crab does not migrate for a long distance, but swims from shallow water to deeper water for the winter with the decrease of water temperature every year 1 1 month, and then swims from deep water to shallow water from April to May in the following year to reproduce, and the breeding period is May to August.

The horseshoe crab is hermaphroditic, and the female is larger than the male. The adult female weighs about 4 kg, and the male weighs about1.8 kg. The female carries the male, inhabiting, crawling and swimming in pairs, which is called Yuanyang in the sea. The fertilized eggs hatch into larvae after 5-6 weeks, and the first hatched larvae are 7-8 cm long, which is called trilobal larvae. After molting for the first time, the larvae grow into juvenile horseshoe crabs, and it takes about 4-5 years from juvenile horseshoe crabs to sexual maturity, molting13-14 times.