Opabinia looked so strange that the audience at the first presentation of Whittington's analysis laughed.[1] The length of Opabinia regalis from head (excluding proboscis) to tail end ranged between 4 centimetres (1.6 in) and 7 centimetres (2.8 in).[2] One of the most distinctive characters of Opabinia is the hollow proboscis, whose total length was about one-third of the body's and projected down from under the head.