104 president's addeess. 



Fauna of tlie great abyss is remarkably characteristic, and pre- 

 serves its peculiar facias everywhere. Many identical forms have 

 been proved, in the few lines of dredgings which have already 

 been taken, to exist in every ocean. Others have occurred at 

 stations separated by many thousands of miles, and everywhere 

 representative species of families, which were unknown to exist 

 prior to these abyssal explorations, are found coming up in the 

 dredge, to bear their testimony that throughout the vast region 

 of the great abyss a special fauna exists, which possesses well 

 marked features of its own, and in all parts is characterized by 

 closely related if not identical species, which are wholly absent 

 from those shallower waters affected by the direct radiation of 

 heat from the sun. 



The fauna found in 100-500 fathoms is extremely rich. It 

 embraces species in every class which on the one hand are not 

 met with at lesser depths, but on the other do not descend to 

 the abyss. At the same time a large portion of shallow water 

 forms descend to this region, while some also of the truly abyssal 

 groups and species begin here to make their appearance. 



In from 500-1000 fathoms the fauna continues to consist of 

 almost all the species which had first appeared in between 100- 

 500 fathoms, though some forms which are found above the 100 

 fathoms line still linger, while the fauna is probably augmented 

 by almost all the species which are truly abyssal, or "benthal," 

 as Dr. Jeffreys has suggested they should be called. At the same 

 time the fauna of this region is not so extensive as that between 

 100 and 500 fathoms. 



In greater depths than 1,000 fathoms the number of species 

 would certainly seem to diminish, and this diminution is carried 

 much further when at about 2,500 fathoms the Globigerina Ooze 

 gives place to the Eed Clay. It has been already observed that 

 the animals at these depths have a peculiar facies of their own, 

 and although all classes have still their representatives, and thus 

 it is indubitably proved that lime-secreting animals can live in 

 the water at this depth, which, at the same time, dissolves shell- 

 structure. It would appear to follow that there must be a con- 

 tinual battle between the animal and the water whether the one 



