Snails are not a biologically taxonomic name, but generally refer to all terrestrial species of gastropods. In general, Western languages do not distinguish between aquatic snails and terrestrial snails, and in Chinese snails only refer to terrestrial species, and snails in the broad sense also include giant shield slugs. A snail is an animal that includes many different families and genera. Feeds on plants and lays eggs in the soil or on trees. It is more common on tropical islands, but some also live in cold areas. Arboreal species are brightly colored, while ground-dwelling species usually have several close colors, generally with stripes. The genus Crystal Snail is the largest in Africa, with more than 20 centimeters. Several species of the European genus Macrosnake are often used as delicacies, especially in France. Snails are the most common mollusks on land and have high edible and medicinal value.
The entire body of the snail includes shells, head, neck, shell membranes, feet, internal organs, sacs and other parts, and the back of the spiral shell.
Snail structure diagram
Its shapes are various and different in size, including pagoda shape, gyroscope shape, conical shape, spherical shape, pipe shape and so on. At present, the domestically bred white jade snails, large cover snails, scattered large snails, bright large snails, brown cloud agate snails, etc. have their own unique shapes.
<h3>Prosobranchia</h3>
The biggest difference between the body structure of prosobranchia snails and Pulmonata is the distinction between sex and its respiratory system. Pre-gill snails are hermaphrodites, while lung-like snails are hermaphrodites; in addition, pre-gill snails breathe in gills and lung snails breathe in the lungs. Most of the snails known to have lungs, so relatively few types of pre-gill snails are found.
Pearl snail superorder (Neritopsina)
The pearl snail Neritopsina has fewer snail species and is mostly small and not easily detectable. They all have a half-moon shaped calcareous mouth cap, a pair of antennae, and eyes born at the base of the antennae. There is only one superfamily, Neritoidea, and the hydrocenidae and Helicinidae, to which the superfamily belong, and there are not many species.
New gastropods (Caenogastropoda)
The newly entered gastropod (Caenogastropoda) has few snail species and is slightly larger than the pearl snail superorder. Their snails have calcareous or mouth caps and are multi-rotating or rounded. The head has a pair of antennae, the eyes are born at the base of the antennae, and some kinds of shells have relatively special suture tubes. In addition, there is no olfactory sensor on the coat cavity of the snail of this superorder. There are two superfamilys under this superfamily, namely the cyclophoroidea of the architaenioglossa and the sulphusoidea of the Sorbeoconcha family, and the shellfish in the suede superfamily of the suede snail superfamily mostly live in the intertidal zone and freshwater waters, so some of the shellfish in this superfamily are not snails.
<h3>There are lungs (Pulmonata</h3>).
Lung snails (Pulmonata) make up the majority of snails, have lungs in the body for breathing, and are hermaphrodite. Among the lung-bearing species, Eupulmonata accounts for the majority, and the snails of the order Eupulmonata are the most common snails in the order Stylommatophora.
Eupulmonata
True lungs make up the majority of snails, with a spiral-shaped shell and no mouth cap. There is no olfactory receptor inside the mantle membrane, and there is a pulmonary hole at the outlet that can be contracted. In 1998, Smith and Stanisic proposed dividing eupnephalus into three suborders, including actophila, trimusculiformes, and stylommatophora.
Actophila
Most of the shellfish of the suborder Coastal Snail, such as the ear snail, live in the intertidal zone, and only a few belong to snails, such as the poppy snail in Taiwan. The snail eyes of this suborder are born at the base of a pair of antennae on the head , and the shell mouth is mostly toothed.
Suborder Trimusculiformes
Most of the shellfish of the suborder Pseudospinus are born in the intertidal zone , and only a few belong to snails , such as snails. Ben suborder shellfish have a bucket-like shell with a lung tube on the right side of the shell, a pair of antennae on the head that have degenerated, and eyes at the base of the antennae.
Stylommatophora
The stalk-eye suborder snail is the most common snail, with two pairs of antennae, and the eyes are born at the apex of the upper antennae. In particular, the eyes of the suborder snail will begin to contract inward from the top when they contract.
<h3>Anatomical illustrations</h3>
(Figure) Anatomical illustration
Anatomical illustrations:
1, shell , 2, liver, 3, lungs, 4, anus, 5, breathing holes, 6, eyes, 7, tentacles, 8, cranial ganglia, 9, salivary catheter, 10, oral cavity, 11, sac,
12, salivary glands, 13, reproductive foramen, 14, penis, 15, vagina, 16, mucus glands, 17, fallopian tubes, 18, sagittal sac, 19, foot 20, stomach 21, kidney 22, inciso 23, heart 24, vas deferens
This article was edited by headline encyclopedia user Xiao Huan, user 2149794967371.