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In gastropods in many ancient lineages, the gills are bipectinate, having an overall shape that is similar to a bird's feather, with narrow filaments projecting either side of a central stalk. Gastropods such as abalone and keyhole limpets have two gills, which is believed to be the arrangement in the earliest fossil gastropods. The water ...
In the most primitive gastropods, however, the stomach is a more complex structure. In these species, the hind part of the stomach, where the oesophagus enters, is chitinous, and includes a sorting region lined with cilia. [1] In all gastropods, the portion of the stomach furthest from the oesophagus, called the "style sac", is lined with cilia.
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
The Human Cell Atlas project, which started in 2016, had as one of its goals to "catalog all cell types (for example, immune cells or brain cells) and sub-types in the human body". [13] By 2018, the Human Cell Atlas description based the project on the assumption that "our characterization of the hundreds of types and subtypes of cells in the ...
Gastropods have the greatest numbers of named mollusk species. However, estimates of the total number of gastropod species vary widely, depending on cited sources. The number of gastropod species can be ascertained from estimates of the number of described species of Mollusca with accepted names: about 85,000 (minimum 50,000, maximum 120,000). [9]
This outline is provided as an overview of, and organized list of articles relevant to, the subject of gastropods (snails and slugs): Gastropod – any member of the class Gastropoda, which includes slugs and snails.
The majority of gastropods have haemolymph containing the respiratory pigment haemocyanin. This is a copper-containing protein that helps to carry oxygen, and gives the haemolymph a pale blue colour. In the freshwater Planorbid snails, however, the haemocyanin is replaced by haemoglobin , and thus their haemolymph is red rather than blue.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda (members of these classes include saltwater and freshwater snails, clams, octopus, squid and relatives). Siphons in molluscs are tube-like structures in which water (or, more rarely, air) flows.