FISHES OF THE CHALK. 
U1 
Esox or Pike, is very analogous, and in all pro- 
bability, tlie relic before us will be found to belong 
to an extinct or unknown species of that genus. 
The lower jaw is nearly perfect, and is attached 
to the chalk ; of the upper, a part only remains. In 
the lower there are nine teeth in situ ; these are not 
fixed in sockets, but united to the jaw by anchylosis. 
They have a glossy surface, and are exceedingly 
brittle ; differing most essentially in this respect 
from those of the shark, and other fishes previously 
noticed. The two anterior teeth are nearly an inch 
in length, and possess a very peculiar form ; they 
are broad at the base, and suddenly contracting, 
terminate in a point ; they are convex behind, and 
rather channelled in front. The teeth are of vari- 
ous sizes ; some being very short, and not attached 
to the edge of the jaw, but to a longitudinal depres- 
sion on its inner surface. They are very irregularly 
disposed, and appear to have suffered some degree 
of displacement. 
The ichthyolite we have next to describe, is in 
all probability abdominal, but the situation of the 
fins is so imperfectly known, that even this point is 
not positively ascertained. The determination of 
its generic characters is involved in still greater 
obscurity, and there does not appear to be any 
recent genus to which it can be correctly appro- 
priated. It bears some affinity to the Antherina 
Mugil, and Polynuiemus, but possesses characters 
obviously distinct from either of those genera. In 
the elongated form of the body, the number and 
situation of the fins, and in the dentature of the 
jaws, it resembles an ichthyolite figured by Cu- 
