Morphological characteristics of the family spiridae
Neritidae (scientific name: Neritidae) is a family of paleogastropoda of Gastropoda. The shell is nearly spherical or hemispherical, the shell is thick, the spiral part is low and small, the body spiral layer is expanded, and the surface surface is spiral rib or smooth. The shell is semilunar or ovoid, the inner lip is wide and thick, and the middle part is often dentate or smooth without teeth; it is calcareous and semicircular. They are mainly distributed in tropical areas and inhabit on the rocky bottom of intertidal zone, and some species inhabit in estuaries or streams injected with a small amount of seawater. It mainly feeds on seaweeds. About 40 species have been found in China and distributed in the southeast sea area.
The conch has a spherical or hemispherical shell with a thick shell. The two lips of the shell often have dentition. The cuticle is semicircular or chicken heart-shaped with a handle like protuberance on the inside. According to the observation, the snails have the characteristics of avoiding light, backwardness and strong water storage capacity. Therefore, they often like to climb into the dark corner of the crevices of reefs above the high tide line. When the drizzle is continuous or at night, it is the activity time of the snails. Except for the rarity of the snails, the other species are quite abundant.
The shell is nearly spherical, with eyes at the base of the antennae. The mouth cap is semicircular and has a handle like protuberance. Special skills: drought resistance, slow crawling speed, two advantages of spherical shells, dissolution and reabsorption of calcium carbonate in the body, color protection, big steel teeth, and evolution mode adapting to various environments.
Most of them live in the coastal intertidal zone, and a few live in fresh water or soda water zone. They are very few of the shellfish that can cross the sea and rivers. Evolution: since it appeared on the earth 380 million years ago, the species has gradually increased, and there is an evolutionary tendency towards terrestrial life. The tree snail among the land shells evolved from the snail.
Marine products inhabit in the intertidal reef area, freshwater habitat in the riparian rocks or mangrove swamp areas, all of which are herbivorous shellfish that feed on algae, and have the characteristics of avoiding light and backland. I like to live in groups.
No reproduction in fresh water
Black jade snail
Life span: about 3-5 years, about 20 months to reach sexual maturity.
1. Insemination in vivo
2. Single kidney, single gill and single auricle
3. The nacre is not developed
4. Living environment across the sea and fresh water
1. Fish boat snails
3. Oncomelania Bleeker
5. Dashed concha
7. Oncomelania variegata
8. Oncomelania macrocephala
9. Oncomelania nigra
11. Oncomelania pisiformis
12. Wall snail
13. Pearl snail