and at depths ranging from two thousand five hundred fathoms to five 

 thousand fathoms is the bottom of the ocean. The inhabitants of the deep 

 sea are curious animals, the shells being often of exquisite beauty, both in 

 texture and in color ; and are often covered with an epidermis similar to 

 that of fresh-water shells. The bodies of the animals from these regions 

 are flabby and gelatinous in appearance when brought to the surface, but 

 it is believed by scientists that in their native places, under the terrific 



pressure of a depth of two or three miles 

 below the surface, which cannot be less 

 than one thousand pounds to the square 

 inch, their bodies are compressed to the 

 consistency of iron or steel wire. It is 

 also believed by some conchologists that 

 every molecule of animal matter in the 

 body of the mollusk is in actual contact 

 with a molecule of sea-water. How this 

 can be and the animal still perform the 

 functions of life is not known, but this 

 seems to be the only theory that will ac- 

 count for their ability to withstand such 

 enormous pressure. 



"When the operculum is present in 

 deep-sea shells it is horny, and very small 

 when compared to the size of the aper- 

 ture. That light is present in these great 

 depths we are assured from the presence 

 of well -formed eyes in these animals, 

 many of these organs being out of all 

 proportion to the size of the animal. 



" It is also interesting to note the 

 temperatures under which many deep-sea animals live. At a depth of 

 about eight hundred fathoms it is forty degrees Fahrenheit, and from 

 this depth, the temperature falls one-tenth of a degree for every hun- 

 dred fathoms until the freezing-point is reached. It is not to be sup- 

 posed, however, that the water in these extreme depths ever actually 

 congeals. 



"A large number of deep-sea mollusks have been discovered by the 

 United States Fish Commission's steamers Albatross and Blake, and the 

 British steamer Challenger, and the material collected has been described 

 and figured by such well-known biologists as Dr. W. H. Ball, Professor 

 A. E. Verrill, Rev. Boog Watson, and others. Many interesting accounts 



88 



Calliostoma bairdii, a deep-water 

 mollusk, dredged in the Atlantic Ocean 

 at a depth of from 56 to 640 fathoms. 

 Dorsal view of living animal and shell. 

 (Verrill.) 



