As of yet, only 2% of the ocean has been explored. And last year alone, over 13,000 previously undiscoverd new species were discovered. So what does one call an undiscovered species?(Remember, to sound like a salty sea dog, you say "sarpent," not "serpent.") Link
In 1892 Dr. Anthonid Cornelis Oudemans, director of the Dutch Royal Zoological Gardens at the Hague, published his definitive work on cryptozoology – long before cryptozoology was even a popular idea. Titled The Great Sea-Serpent, this comprehensive work not only describes some 150 sightings (dating back to the 16th century) but also presents various hoaxes and alternative theories.