18 



northern limit, yielding in vigour and stature in pro- 

 portion to its distance from the equator where it attains 

 a height of two hundred feet, towering over every 

 other tree of the forest. At lat. 43 N. in Europe it 

 can only be recognised by its characteristic foliage. 

 In America its limit is 35 N. lat., being represented 

 by Sabal Adamsonii, Guern., a shrub with small leaves, 

 in striking contrast to the lofty Sabal umbraculifera, 

 Mart., of the Antilles. A similar degeneration is met 

 with in the southern hemisphere, and in proportion as 

 the distance from the equator increases so does the 

 palm diminish in height, and the trunk become stunted 

 and thickened. In Chili at 36 South lat., the last 

 palm, Jubcea spectaUlis, Humb., and in Africa at 35 

 55 'S. lat., Phoenix reclinata, Jacq., grows, whose short 

 axis gives no idea of the magnificent date, which is the 

 type of that family. It is curious, the palm which 

 grows on the highest latitudes of the northern hemis- 

 phere has fan-shape leaves, and that of the southern 

 hemisphere has pinnate leaves such is Kentia sapida^ 

 Mart., which grows in New Zealand at 3S 22' S. lat. 



Let me, in conclusion, say I have laid before you 

 abundant proofs of the great variations animals, and 

 especially plants, have undergone in past ages. There 

 are many missing links no doubt still to be filled up. 

 Every new discovery is a fresh link to bring the 

 organic elements of geological formations, widely apart 

 as to time, in connection with, or part of one great 

 harmonious organic system. The various changes 

 which the earth has experienced through depressions, 



