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ated form observable on several pebbles. I have very little doubt of 
these fossils deriving their forms from some lost or unknown species 
of this genus. 
The first specimen of this kind which attracted my notice, is a flint 
stone which I picked up in the gravel-pits near Hackney-road. This 
is represented Plate XYI. Fig. 18. The regularity of the transverse 
striae on the round trachea-like body which they compose, and the 
smooth surface of the valve-like body in which they terminate, gave 
me at first an idea, not only of its having derived its figure from animal 
organization, but of its affinity to the barnacle. 
The opinion which I at first formed, received corroboration from 
different specimens which I afterwards met with. In some of these 
specimens, both the shelly valve and the cartilaginous peduncle are 
very distinctly defined. The form of the valve is distinct ; and the 
membraneous or cartilaginal part of the peduncle is apparently, I could 
almost say obviously, in a corrugated and contracted state ; and the 
commencement of the valve is bordered by a regular and well defined 
line : this, indeed, is the case with the specimen here represented. 
At the sale of the Leverian Museum I purchased a specimen, which 
I suspect to be an English flint, although labelled “ A pretty coral, 
from the East Indies.” In this fossil are apparently two distinct 
peduncular bodies, with their attached valves : one displayed on the 
upper, and the other turned round on the under surface of the stone. 
In another specimen, four of these trachea-like bodies appear to have 
been united in one central body, by those ends most remote from 
the part which I have named the valve. But whether this fossil has 
belonged to the genus AnatiJ'a or not, the different states in which 
the trachea-like body is seen, almost demonstrate that it was a part 
capable of elongation and contraction, as circumstances required. 
It is evident that many of the rugous and striated pebbles have formed 
parts of this fossil body : others, undoubtedly, owe their rugae to other 
fossils ; among which, I believe, the orthoceratites may be mentioned. 
