The inner limbs of the male's first pair of abdominal limbs are deformed and become grasping devices, which are used to support the female's body during mating. The last pair of appendages in the abdomen are developed tail limbs, including one primitive limb, two outer limbs and one inner limb, which are flaky. There is a powerful forked spur on the inside of the original limb, called the basal process or double spur, which extends between the inner and outer limbs. The tail fan composed of tail limbs and tail joints can not only swim, but also be used to dig holes and defend the enemy.
The shrimp's mouth is located between the two jaws on the ventral surface. The mouth enters the stomach through the esophagus, then connects with the intestine, vertically passes through the abdomen and then returns to the anus. The anus is open on the ventral surface of the caudate segment. The heart is long and tubular, extending from the back of the head and chest to the fifth abdominal segment. The heart extends arterial blood vessels to both sides and back and forth, leading to various organs and tissues.
The female genital foramen is paired, mostly on the ventral surface of the sixth thoracic segment. The ovaries are located on the back of the body below the heart. When pregnant with eggs, they extend backward from the head and chest through the abdomen to the tail. A pair of male genital holes are located on the ventral surface of the thoracic terminal segment. The submandibular gland at the base of the second antenna of the head is the excretory organ.
Its breeding period is from April to September, and its peak period is from May to July. During the breeding season, the 4th to the caudal segment of the ovary is yellowish brown, with melanin distributed in the back and concentrated pigment in the midline of the body axis. The thickness of the ovary is the largest in the 5th and 6th segments, and the caudal segment is enlarged, full of caudal segment and fan-shaped. Testicles are milky white. The average number of eggs laid by Oratosquilla oratoria is 30,000 ~ 50,000, and most of them are 200,000.
Extended data
Squid lives in caves in coastal waters, but it can also be seen at a depth of 1300 meters (about 4300 feet). Caves are often dug at the bottom of sand or sediment in shallow water, and are mostly U-shaped. Both larvae and adults are good swimmers. It is a carnivore that preys on small invertebrates and feeds on other crustaceans and small fish, coastal earthworms and nereis. This animal can make a sound by rubbing the ventral surface of the caudal segment with its tail limb or tapping with its left limb.
Southern mantis is common in Mediterranean and adjacent Atlantic waters. It is 20 cm (about 8 inches) long and lives in sediments and organic debris. Liriomyza huidobrensis is the most common species along the Atlantic coast of North America. The oral shrimps along the coast of Japan are edible, with a body length of 20 cm.
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