PLESIOSAURUS. 
21 1 
series of links and gradations, from the corres- 
ponding parts of the highest mammalia, to then- 
least perfect form in the fins of fishes. In the 
fore paddle of the Plesiosaurus, we have all the 
essential parts of the fore leg of a quadruped, 
and even of a human arm ; first the scapula, 
next the humerus, then the radius and ulna, 
succeeded by the bones of the carpus and meta- 
carpus, and these followed by five fingers, each 
composed of a continuous series of phalanges, 
(see PI. 16 , 17 , 19 .) The hind paddle also offers 
precisely the same analogies to the leg and foot 
of the Mammalia; the pelvis and femur are 
succeeded by a tibia and fibula, which articulate 
with the bones of the tarsus and metatarsus, 
followed by the numerous phalanges of five lono- 
toes. 
Prom the consideration of all its characters, 
Mr. Conybeare has drawn the following infe- 
rences with respect to the habits of the Plesio- 
saurus Dolichodeirus, “ That it was aquatic is 
evident, from the form of its paddles ; that it 
Was marine is almost equally so, from the re- 
“lains with which it is universally associated ; 
sail more numerous and angular joints of the paddle of the 
yosaurus, and the phalanges of land quadrupeds, which are 
tor cylindrical ; in these sea Lizards they were flattened, 
^ c purpose of giving breadth to the extremities as organs of 
"ig. As its paddles give no indication of having carried 
the claws, as those of the Turtles and Seals, 
c esiosaurus apparently could have made little or no prooress 
any other element than water. 
