FLOOR.] 
FOSSILS. 
175 
preservatives. They form two important sections — the Ctenoids and 
the Cycloids. The Ctenoids, which are distinguished hy their scales 
being serrated, or finely notched at the free edge, are arranged in 
compartments 23 to 26 : the common Perch is a good example of this 
group. The Cycloids occupy the compartments 27 to 36. Their 
scales have the edges smooth. The Fishes of the Mackerel tribe 
(Scomberidce), of the Carp tribe (Cyprinidce), of the Pikes (Esocidce), 
and the Herrings (Clupeidce), may be noticed as forming the more 
important families of this division. 
ROOM III. 
Excepting Case 11 and part of Case 7, the whole of the Wall Cases 
in this room are devoted to Reptilian remains ; and amongst them may 
be first noticed the Dinosaaria, which group contains the largest ter- 
restrial species, such as the Iguanodon and Megalosaurus. In the 
Middle Case (No. 9), on the north side of the room, are arranged the 
remains of the gigantic Iguanodon : firstly, and in the centre, the 
large slab of Kentish rag from Mr. Bensted's quarry near Maidstone, 
containing a great portion of the skeleton of a young individual ; to 
the right of this will be found portions of the skull and lower jaw, and 
the teeth of different specimens of the same species; and to the left, 
extending to Case 8, are nearly all the more characteristic parts of the 
skeletons of various Iguanodons, chiefly from the Wealden formation 
at Tilgate, and in the Isle of Wight. These specimens are mostly 
from the collection of the late Dr. Mantell. On the lower shelves 
to the right of the centre case containing the Iguanodon will also be 
found the almost entire remains of another land reptile called Sceli- 
dosaurus, from the Lias of Charmouth, Dorset. The remainder of the 
Case to the left (No. 8) is occupied by the remains of other gigantic- 
reptiles from the Wealden and upper Oolitic formations, including tho 
Megalosaurus and Cetiosaurus. In the centre of Wall Case 8 is dis- 
played a considerable portion of the skeleton of a remarkably large land 
reptile (Omosaurus armatus, Owen) recently discovered in the Kim- 
meridge Clay at Swindon, in Wiltshire. On the right of the 
centre Case No. 10, in the two first compartments, will be found 
the remains of the Hylceosaurus, including the large block from 
Tilgate Forest, discovered by Dr. Mantell, which contains a considera- 
ble series of vertebrae, dermal spines, and other parts of this singular 
reptile. The dermal spines and other remains of the Polacanthus, a 
new Wealden reptile from the Isle of Wight, are arranged in Case 9 ; 
and on the top of the same Case is a new species of Plesiosaurus 
(P. laticeps, Owen). 
The remainder of this Case is occupied by the fossil Crocodiles. 
Among the specimens may be noticed the slender-snouted Crocodi- 
lians, in which the vertebrae are bi-concave, including the Teleosaurus 
Chapmanni, from the Lias of Whitby, and other Teleosauri from 
the Lias and Oolites of Germany and France. Among the Croco- 
dilians with the ordinary form of vertebras, the body, or central part, 
