2U 
MARINE SAU RIANS. 
are the most exalted : thus, the fin of the fish 
becomes the paddle of the reptile Plesiosaurus 
and Ichthyosaurus; the same organ is con- 
verted into the wing of the Pterodactyle, the 
bird and bat ; it becomes the fore-foot, or paw, 
in quadrupeds that move upon the land, and 
attains its highest consummation in the arm 
and hand of rational man. 
I will conclude these observations in the 
words and wdth the feelings of Mr. Conybeare, 
which must be in unison with those of all who 
have had the pleasure to follow him through his 
masterly investigations of this curious subject, 
from which great part of our information re- 
specting the genus Plesiosaurus has been de- 
rived : 
To the observer actually engaged in tracing 
the various links that bind together the chain of 
organised beings, and struck at every instant by 
the development of the most beautiful analogies, 
almost eveiy detail of comparative anatomy, 
however minute, acquires an interest, and even 
a charm ; since he is continually presented w ith 
fresh proof of the great general law, w^hich 
Scarpa himself, one of its most able inve.sti- 
gators, has so elegantly expressed : ‘ Usque adeo 
natura, una eadem semper atque multiplex, dis- 
paribus etiam formis effectus pares, admirabili 
quadam varietatum simplicitate conciliat.’ ” 
