Cell wall the cell membrane is the bacterial cell wall. Bacterial cell walls are made of peptidoglycan (also called murein), which is made from polysaccharide chains cross-linked by unusual peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi which are made of cellulose and chitin, respectively. The cell wall of bacteria is also distinct from that of Archaea, which do not contain peptidoglycan. The cell wall is essential to the survival of many bacteria, although L-form bacteria can be produced in the laboratory that lack a cell wall. The antibiotic penicillin is able to
Crustacean the zoea stage is followed by the mysis stage, and in others, by the megalopa stage, depending on the crustacean group involved. The name "crustacean" dates from the earliest works to describe the animals, including those of Pierre Belon and Guillaume Rondelet, but the name was not used by some later authors, including Carl Linnaeus, who included crustaceans among the "Aptera" in his '. The earliest nomenclaturally valid work to use the name "Crustacea" was Morten Thrane Brünnich's ' in 1772, although he also included chelicerates in the group. The subphylum Crustacea comprises almost 67,000 described species, which is thought