‘MARINE BIOLOGICAL STATION AT PORT ERIN. 43 
longer than the time when there was a very nearly similar 
_ fauna at both poles. However, the faunas of the sea are now 
_ arranged more according to zones of temperature than by 
Land Barriers. The tropics extend polewards as we go down 
: in the geological formations till just before the Chalk there 
_ was a universally warm sea—from equator to poles and from 
top to bottom—say 80° F'.—Coral reefs once flourished at the 
poles. These have now been driven to equatorial regions where 
_ the temperature has remained nearly the above. The animals 
which in the universal warm sea came to live in the mud at a 
little depth, remained behind when cooling of the poles com- 
menced. These animals without pelagic free-swimming larvae 
also descended to the deep sea as the waters cooled. When 
_ the sea was all 70° or 80° F. the deep sea was not inhabited. 
Polar animals and deep sea animals have all a direct develop- 
ment (so also fresh water animals, also derived from the deeper 
part of the shore estuarine universal fauna). 
“Tt is nonsense to suppose that while the earth was 
developing the sun has always been the same as now. It has 
_ been contracting. In Chalk times it had a diameter seen from 
the earth equal to an angle of 10° in the heavens. This would 
give all the heat and light that is necessary for a great Carboni- 
 ferous forest at the poles. 
~ “You can tell me how much of this is d——d nonsense. 
“Yours sincerely, 
“Joun Murray. 
“ Fresh water fauna is much more archaic than deep sea.” 
One of the theories which he supported, and which is not 
now generally accepted, although he believed he had much 
evidence in favour of it from the “Challenger” results, was 
the theory of “ Bipolarity,” viz., that identical organisms 
were found in arctic and antarctic seas and not in intermediate 
waters, and that they represented the original marine fauna 
which at some earlier period of the earth’s history inhabited 
