Kidney always so simple; in cartilaginous fish and some amphibians, there is also a shorter duct, similar to the amniote ureter, which drains the posterior (metanephric) parts of the kidney, and joins with the archinephric duct at the bladder or cloaca. Indeed, in many cartilaginous fish, the anterior portion of the kidney may degenerate or cease to function altogether in the adult. In the most primitive vertebrates, the hagfish and lampreys, the kidney is unusually simple: it consists of a row of nephrons, each emptying directly into the archinephric duct. Invertebrates may possess excretory organs that are sometimes referred to as
Bladder pipe Bladder pipe The Bladder pipe ("German": Platerspiel or Blaterpfeife) is a medieval simplified bagpipe, consisting of an insufflation tube (blow pipe), a bladder (bag) and a chanter; sounded by a double reed, which is fitted into a reed seat at the top of the chanter. The reed, inside the inflated bladder, is sounded continuously, and cannot be tongued. Some bladder pipes were made with a single drone pipe, and reproductions are similar to a loud, continuous crumhorn. The chanter has an outside tenon, at the top, near the reed, which fits into a socket or stock, which is then tied