Dusky smooth-hound fishes is their ability to continually replace the teeth in their upper and lower jaws. Smooth dogfish differ from other sharks because of their 10 rows of flat, blunt teeth. The teeth in the upper and lower jaws are similar in size and are asymmetrical with rounded cusps. These teeth are used to crush and grind food, rather than bite it. Their unique dentition is important for their crustacean-based diet. In smooth dogfish, tooth replacement is related to body growth. They grow about 10 cm per every six rows of teeth replaced. That is an increase of 0.03 mm per
Welsh Hound Welsh Hound The Welsh Hound (Welsh: "Bytheiad" or Ci Hela Cymreig) is a breed of hunting dog of the foxhound type, indigenous to Wales. The Welsh Hound is a native breed to the British Isles, and could possibly be the Segussi breed of rough coated hound which existed in northern Europe in Roman times. From medieval times through the early part of the twentieth century, the bards, who had always held a special place in Welsh society, sang odes to the hounds, often naming individual hounds, and praising their qualities. "The ancient laws of Wales codified during the reign of