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A slug on a wall in Kanagawa, Japan.. Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod mollusc.The word slug is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semi-slugs (this is in contrast to the common name snail, which applies to ...
Freshwater snails are gastropod mollusks that live in fresh water. There are many different families. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs to major rivers.
Determining whether some gastropods should be called sea snails is not always easy. Some species that live in brackish water (such as certain neritids) can be listed as either freshwater snails or marine snails, and some species that live at or just above the high tide level (for example, species in the genus Truncatella) are sometimes considered to be sea snails and sometimes listed as land ...
The pharynx can be very large, especially in carnivorous species. Many carnivorous species have developed a proboscis , containing the oral cavity, radula, and part of the oesophagus. At rest, the proboscis is enclosed within a sac-like sheath, with an opening at the front of the animal that resembles a true mouth.
This mantle is the part in snails that secretes a shell, but in the black slug, the mantle contains a resilient protective structure of calcareous granules. [6] Arion ater produces three forms of mucus. The first two aid the animal in locomotion, with a thinner mucus coating the animal laterally, and a thicker, more viscous mucus secreted along ...
The two major classes of molluscs have representatives in freshwater: the gastropods (snails) and the bivalves (freshwater mussels and clams.) It appears that the other classes within the Phylum Mollusca -the cephalopods, scaphopods, polyplacophorans, etc. - never made the transition from a fully marine environment to a freshwater environment.
Snails can be found in a very wide range of environments, including ditches, deserts, and the abyssal depths of the sea. Although land snails may be more familiar to laymen, marine snails constitute the majority of snail species, and have much greater diversity and a greater biomass. Numerous kinds of snail can also be found in fresh water.
Pteropoda (common name pteropods, from the Greek meaning "wing-foot") are specialized free-swimming pelagic sea snails and sea slugs, marine opisthobranch gastropods.Most live in the top 10 m of the ocean and are less than 1 cm long.