Decapod anatomy are referred to as the "gonopods". At the end of the pleon is the tail fan, comprising a pair of biramous uropods and the telson, which bears the anus. Together, they are used for steering while swimming, and in the caridoid escape reaction. In crabs and some other carcinised decapods, the abdomen is folded under the cephalothorax. Decapod anatomy The decapod crustacean, such as a crab, lobster, shrimp or prawn, is made up of 20 body segments grouped into two main body parts, the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various
Wall spider Wall spider Wall spider is the common name for members of the genus Oecobius. The members of these several species are all very small spiders that make small flat webs over crevices in walls and in similar spaces. They possess an organ called a cribellum, which is a kind of comb-like device used to separate fibers of silk drawn from its spinnerets into many extremely fine fibers. Those fibers are so small in diameter that prey insects easily become entangled in them. The spiders then bite them before they can get away. One cosmopolitan species is "O. navus" (sometimes also