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and a second specimen, about two feet long, lying outside 
the abdominal aspect of the larger individual, are also well 
displayed. The situation of the smaller specimen has, I un- 
derstand, given rise to various opinions, by naturalists who 
have seen it, as to whether it be in its present place in rela- 
tion to Viviparous origin, or to having been swallowed whole, 
and so taken into the stomach of the larger Ichthyosaurus. 
I bee to express distinctly my conviction that neither of these 
causes will account for its position, as the ribs of the larger 
specimen are covered by the smaller; distinctly proving that 
the’ smaller animal was outside the larger one. I do not 
attempt to define the species, or add a new name to the 
already overburdened list, on which Palzontologists have 
amused themselves, by naming more than thirty species, 
which classification is for the most part based on minute 
differences in the teeth. The present specimen does not show 
a sufficient number of them for positive identification. 
There is the usual break in the line of the caudal vertebre, 
in this specimen, which first suggested to Professor Owen his 
hypothesis as to the necessity for the presence of a caudal 
fin, to enable this large marine Saurian to move swiftly in 
the water, the dislocation always occurring in the same rela- 
tive place, it appeared to him as though there must have 
been the weight of some appendage at the extreme end of 
the tail, which when the integuments were decomposed, 
allowed it to fall and separate from the end of the body. 
Added to this break, there is the depression on the upper 
aspect of the terminal vertebrze, which indicates that the fin 
was vertically placed, asin the shark and other fishes. This 
reasoning appeared so just, that in each of the large restora- 
tions that I made at the Crystal Palace, Sydenham, I adopted 
the vertical caudal fin for the Ichthyosaurus Platyodon and 
Communis. The energetic President and the authorities of 
the College of the City of New York, may be congratulated 
on the acquisition of so good a specimen of this interesting 
fossil, which shows in every part the perfection of Creative 
Power, and which though it lived so many thousands of 
years ago, yet possesses the most finished perfect organic 
