…a large group of arthropods that comprises the arachnids, sea spiders, and horseshoe crabs. They lack antennae, but possess a pair of chelicerae, a pair of pedipalps, and (typically) four pairs of legs…
…a large group of arthropods that comprises the arachnids, sea spiders, and horseshoe crabs. They lack antennae, but possess a pair of chelicerae, a pair of pedipalps, and (typically) four pairs of legs…
…a giant fossil marine arthropod of a group occurring in the Palaeozoic era. They are related to horseshoe crabs, and resemble large scorpions with a terminal pair of paddle-shaped swimming appendages…
…a large marine arthropod with a domed horseshoe-shaped shell, a long tail spine, and ten legs, little changed since the Devonian…
