Gastropods, commonly known as slugs and snails, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.
Bivalvia or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills have evolved into ctenidia, specialised organs for feeding and breathing.
The radula is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula is unique to the mollusks, and is found in every class of mollusk except the bivalves, which instead use cilia, waving filaments that bring minute organisms to the mouth.
Aquatic respiration is the process whereby an aquatic organism exchanges respiratory gases with water, obtaining oxygen from oxygen dissolved in water and excreting carbon dioxide and some other metabolic waste products into the water.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.
The tusk shells or tooth shells, technically the Scaphopoda, are members of a class of shelled marine mollusc with worldwide distribution, and are the only class of exclusively infaunal marine molluscs. Shells of species within this class range in length 0.5–18 cm (0.20–7.09 in). Members of the order Dentaliida tend to be larger than those of the order Gadilida.
Bithyniidae is a family of small freshwater snails with an operculum, aquatic gastropod molluscs in the clade Littorinimorpha.
Freshwater bivalves are molluscs of the order Bivalvia that inhabit freshwater ecosystems. They are one of the two main groups of freshwater molluscs, along with freshwater snails.
The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. Siphonal canals allow for active transport of water to sensory organs inside the shell. Organisms without siphonal canals in their shells rely on passive or diffuse transport or water into their shell. Those with siphonal canals have a direct inhalant stream of water that interacts with sensory organs to detect concentration and direction of a stimulus, such as food or mates. In certain groups of carnivorous snails, where the siphon is particularly long, the structure of the shell has been modified in order to house and protect the soft structure of the siphon. Thus the siphonal canal is a semi-tubular extension of the aperture of the shell through which the siphon is extended when the animal is active.
Marine invertebrates are the invertebrates that live in marine habitats. Invertebrate is a blanket term that includes all animals apart from the vertebrate members of the chordate phylum. Invertebrates lack a vertebral column, and some have evolved a shell or a hard exoskeleton. As on land and in the air, marine invertebrates have a large variety of body plans, and have been categorised into over 30 phyla. They make up most of the macroscopic life in the oceans.
Chrysomallon squamiferum, commonly known as the scaly-foot gastropod, scaly-foot snail, sea pangolin, or volcano snail is a species of deep-sea hydrothermal-vent snail, a marine gastropod mollusc in the family Peltospiridae. This vent-endemic gastropod is known only from deep-sea hydrothermal vents in the Indian Ocean, where it has been found at depths of about 2,400–2,900 m (1.5–1.8 mi). C. squamiferum differs greatly from other deep-sea gastropods, even the closely related neomphalines. In 2019, it was declared endangered on the IUCN Red List, the first species to be listed as such due to risks from deep-sea mining of its vent habitat.
The molluscshell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater.
Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks. Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and the proportion of undescribed species is very high. Many taxa remain poorly studied.
The respiratory system of gastropods varies greatly in form. These variations were once used as a basis for dividing the group into subclasses. The majority of marine gastropods breathe through a single gill, supplied with oxygen by a current of water through the mantle cavity. This current is U-shaped, so that it also flushes waste products away from the anus, which is located above the animal's head, and would otherwise cause a problem with fouling.
The hypobranchial gland is a glandular structure which is part of the anatomy of many mollusks, including several different families of gastropods, and also many protobranch bivalves. This gland produces mucus as well as biologically active compounds. The cephalopod ink sac is a modified hypobranchial gland.
Bathyacmaea nipponica is a species of very small, deep-sea limpet, a marine gastropod mollusk in the family Pectinodontidae.
This outline is provided as an overview of, and organized list of articles relevant to, the subject of gastropods :
Bythinellidae is a family of small freshwater snails with an operculum, aquatic gastropod molluscs in the order Littorinimorpha.
Pneumopulmonata is a superorder of heterobranch pulmonate gastropods belonging to the subterclass Tectipleura. It was defined based on results of phylogenomic studies and named by Krug et al. (2022). The superorder unites all of Panpulmonata except for Sacoglossa.
Pair of large, grey gills visible inside the mantle cavity of a giant squid
