Of crustaceans, land-crabs are remarkable for size and number.
Wasmann, who has compiled a list of nearly 1 50o species of insects, arachnids and crustaceans, inhabiting ants' nests.
Zoologists are familiar with many instances (fishes, crustaceans) in which the protective walls of a water-breathing organ or gill-apparatus become converted into an air-breathing organ or lung, but there is no other case known of the conversion of gill processes themselves into air-breathing plates.
Small crustaceans and other aquatic animals push their way into the bladders and are unable to escape.
Various species among those that are predaceous attack smaller insects, hunt in packs crustaceans larger than themselves, insert their narrow heads into snail-shells to pick out and devour the occupants, or pursue slugs and earthworms underground.