AUSTRALIAN CRAYFISH
Australia has a large and unique crayfish fauna including the largest and smallest species in the world. Crayfish, of all of the freshwater invertebrates of inland Australia, are the most widely recognised and important to the human population and the natural aquatic ecosystems. Crayfish are heavy bodied crustaceans with an enlarged, pincer-like first pair of legs and are known by many common names depending on the area they are found. In New South Wales and Victoria they are called yabbies, in Western Australia the Koonac, Gigly and the Marron, while Queensland has the Redclaw.
What are Crayfish?
Crayfish belong to a group of animals called Crustaceans and are part of the phylum Arthropoda. Other Arthropods are insects (Insecta), spiders (Arachnida), and centipedes and millipedes (Myriapoda). All Arthropods have a hardened outer shell, called cuticle (made from calcium carbonate) that acts as a skeleton. Crustaceans are distinguished from the other arthropods by their two pair of antennae - an outer pair called antennae, and an inner pair called antennules. Crayfish bodies are divided into three parts; the head, the thorax (the section that contains the legs), and the abdomen (or the tail, which is the edible part of many large crustaceans including crayfish, prawns and lobsters). Crayfish, like many crustacean have a carapace or shield which projects backwards from the head and covers all of the thorax The carapace has two functions; firstly it protects the delicate feather-like gills which branch off from the base of the legs, and secondly it provides a water channel that is a constant flow of oxygenated water to pass over the gills and enables the crayfish to brea
请大家不要用机器翻译。。。