112 



THREE CRUISES OF THE " BLAKE.' 



a temperature of over 80 Fahr., which decreases gradually with 

 the depth, till, between 600 and 700 fathoms, it has fallen to 



Fig. 395. Ophioconis miliaria. !,'. 



39i. The American continents on one side, and the Antilles 



Fig. 39f>. Ophiomusinm planum. 



on the other, furnish those great land masses the neighborhood 

 of which seems essential to rich and varied marine life. Their 



