PLESIOSAURUS. 
203 
Camelioii, and the paddles of a Whale. Such 
are the strange combinations of form and struc- 
ture in the Plesiosaurus a genus, the remains 
uf which, after interment for thousands of years 
amidst the wreck of millions of extinct inhabi- 
tants of the ancient earth, are at length recalled 
to light by the researches of the Geologist, and 
submitted to our examination, in nearly as per- 
fect a state as the bones of species that are now 
existing upon the earth. 
The Plesiosauri appear to have lived in shal- 
low seas and estuaries, and to have breathed air 
like the Ichthyosauri, and our modern Cetacea, 
^e are already acquainted with five or six spe- 
<^ies, some of which attained a prodigious size 
^ud length ; but our present observations will 
1^0 chiefly limited to that which is the best 
known, and perhaps the most remarkable of 
them all, viz. the P. Dolichodeirus.* 
* The first specimens of this animal were discovered in the lias 
of Lyme Regis, about the year 1823, and formed the foundation 
of that admirable paper (Geol. Trans. Lond. vol. 5, Pt. 2.) in which 
Conybeare and M. De la Beche established and named this 
genus. Other examples have since been recognised in the same 
orraations in different parts of England, Ireland, France, and 
errnany, and in formations of various ages, from the muschel 
n k upwards to the chalk. The first specimen discovered in a 
^nte approaching to perfection, was that in the collection of the 
^nke of Buckingham, (figured in the Geol. Trans. Lond. N. S. 
° ■ b Pt. 2, PI. 48). Another specimen, nearly entire, in the 
00 ection of the British Museum, eleven feet in length, is figured 
our second volume, (PI. 16); and at PI. 17, a still more per- 
