“Wuatss, Porpoises, and Dolphins form a large group of Mammals specially modified for the needs of an aquatic existence, having no external traces of hind-limbs, the fore-limbs in the form of paddles, the tail expanded into a horizontal fin, or “ flukes,” and the nostrils situated on the top of the head, generally remote from the muzzle, and opening by a single or double “ blow-hole.”