The question as to the existence of life at great depths was still a matter of controversy in the last century. In spite of the fact that the remains of living animals were recovered from several hundreds of metres, many marine biologists hesitated to believe that animal life could exist in deep-sea conditions. In 1841, Sir James Clark Ross, the leader of the British Antarctic Expedition, claimed:‘… and although contrary to the general belief of naturalists, I have no doubt that from however great a depth we may be able to bring the mud and stones of the bed of the ocean, we shall find them teeming with animal life; the extreme pressure at the greatest depth does not appear to affect these creatures; hitherto we have not been able to determine this point beyond a thousand fathoms, but from that depth several shellfish have been brought up with the mud’ (Murray 1895, p. 79). Edward Forbes, naturalist on H.M.S.S. Beacon, for instance, referred to the marine environment in excess of 550 m as the ‘azoic zone’. But the classical deep-sea expeditions in the second half of the nineteenth century, among others the famous voyage of the Challenger, produced overwhelming evidence for a more or less abundant abyssal fauna.