Woodlice are crustaceans, like crabs and lobsters. They have gills like them, not lungs, so they only live in damp places!
Crab classification: Phylum - Arthropoda Subphylum - Crustacea Class - Malacostraca Order - Decapoda
Crustaceans are the only arthropods with two pairs of antennae
Arachnids differ from other arthropods in that they have no antenna (nor wings, like many insects). They also use book lungs to breathe, rather than the gills or spiracle/trachea configuration. They have a body plan of only two sections (tagmata) and eight legs, although often with a modified forward pair different from most other arthropods.
Crabs and lobsters are arthropods. In colloquial speech the term "bug" generally refers to arthropods on land, mostly insects and arachnids. In scientific terms the only true bugs are insects in the order hemiptera, excluding crustaceans, which are not insects.
Crustaceans have exoskeletons, two pairs of antennae, two pairs of maxillae, biramous legs, and mandibles, which are like jaws.
Crustaceans are unique because they are protected by a hard exoskeleton. They are the only arthropods with two pairs of antennae. They also have two pairs of maxillae, mandibles, which are like jaws, and have biramous legs, which means they bend in two places.
No. Leeches are annelids, also known as segmented worms.
Arthropods are only one group of invertebrate animals. There are many other invertebrates in the world. Some examples would include single-celled animals, worms, jellyfish, gastropods like slugs and snails, and echinoderms like starfish and sand dollars. Most animals in the world are, however, in the arthropod category. WikiAnswers
Arachnid is a biological category that includes spiders, mites and ticks. Arachnids belong to the larger group of arthropods, which includes insects and crustaceans. All arthropods are distinguished by what is known as a chitinous exoskeleton, which means that they have a hard outer shell made of a protein called chitin, which is what supports the shape of their bodies, unlike mammals such as us, who have internal skeletons. Arachnids have eight legs, unlike insects who have only six.
Hagfish and lampreys have gills. They are the only living members of a primitive group of fish without jaws. They have round sucker-like mouths.
Gills or gill-like organs are found in various groups of aquatic animals, such as mollusks, fishes, crustaceans, insects, and amphibians. Please see the related link below for more information: