VIII. 
THE DEEP-SEA FAUNA. 
Ir is vain to inquire what animals and plants could have 
lived in the primordial ocean. We can only conjecture, if we 
adopt the speculations of Mallet regarding the conditions of 
the ocean, that they must have been capable of bearing an 
intense degree of heat, and probably inhabited a mass of boil- 
ing mud. 
Whole classes of animals and plants live only in the water, 
and cannot subsist elsewhere : water penetrates all their tissues, 
and from it they take the elements needed for their growth. 
Animals living in salt water, with very few зарана die in 
fresh water, probably from the lack of soluble salts. There 
are vast numbers of animals whose function seems to be the 
distribution of the soluble salts which have from time imme- 
morial been swept into the sea. Globigerine, pteropods, mol- 
lusks, echinoderms, corals, and sponges, all distribute over the 
floor of the ocean, in the form of shells or solid calcareous skel- 
etons, the lime and silica which they have derived from the sea- 
water. 
In an atmosphere saturated with moisture, crustacea could live 
under moist stones and bark. Lichens as well as many infuso- 
ria, which when dry remain inert, but are resuscitated by moist- 
ure again, may have formed the prineipal elements of the fauna, 
and have survived during the transition from the older marine 
to a very moist climate, or one resembling the climates of the 
present day. Similar adaptations may have led to the gradual 
change of ‘marine shells into terrestrial types. In fishes proper 
! Sharks are known to inhabit Lake on the shores of northern Brazil extend 
Nicaragua and the fresh waters of some far up the Amazons, and some hydroids 
of the larger rivers of India ; many marine flourish in fresh water. 
fishes, delachians, and cetaceans common 
