136 THE STORY OF LIFE IN THE SEAS. 



surprising that the naturalists at the beginning 

 of the century believed that no animals could 

 possibly live on the floor of the great oceans. 

 Their beliefs, however, merely afford us an 

 example of the danger of prophesying without 

 knowing, for the great expeditions which have 

 investigated the ocean bed during the last thirty 

 years have proved the existence of a rich and 

 peculiar Fauna in all the great depths that have 

 been dredged. The general results of these in- 

 vestigations have been recently summed up by 

 Dr John Murray in the last volume of the Chal- 

 lenger Eeports. He points out the extraordinary 

 variety of life in the deep sea as shown by the 

 contents of the dredge. " At Station 146 in the 

 Southern Ocean, at a depth of 1375 fathoms, the 

 200 specimens captured belonged to 59 genera 

 and 78 species." He can find no record of 

 species equal to this in depths of under 50 

 fathoms, and concludes that the evidence at 

 present before us is sufficient to warrant the 

 belief that the great depths of the ocean are as 

 a general rule extremely rich in species. 



From what has been already said, it may be 

 gathered that nearly all the most important 

 groups of marine animals have representatives 

 in the deep sea. There are Fish, Tunicates, 

 Crustaceans, Molluscs, Echinoderms, Worms, 

 Ccelenterates and Protozoa. Nearly all of these 

 are so modified, either in form or colour, or the 

 structure of their organs of sense, or in other 

 particulars, that they could be recognised at once 

 in a collection as deep-sea animals ; but there is 

 a small minority which seem to have undergone 





