49 
well illustrated by the labours of Brander and Solander. But, whilst 
the Hampshire fossils are generally broken, from the very soft and 
fragile state to which they are reduced by the mud in which they are 
involved, the iossil shells of France are found in the highest state of 
piesei\ ation : and hence numerous species, which can in this island 
e hardly evei obtained, are there found in a perfect state. How 
assiduously and successfully M. Lamarck has employed these several 
advantages, will be manifested by the arrangement he has formed, 
and the important observations which he has made. 
testaceous molluscs; he considers the cephalous, from being 
e most perfect, as^ being proper to form the first order. With the 
exception of the chiton, all the other cephalous conchyliferous mol- 
lusc®, he observes, are simply univalves, whilst the acephalous are 
inclosed in two or more valves. 
Genus I. Chiton. An oblong-elliptical, convex, multivalved shell ; 
wd 1 transverse valves, partly lying over each other, in a row, on the 
back of the animal. 
The only notice which I find taken of the fossil remains of this 
animal is by Lamarck, who states, that the separated valves only are 
ound at Gngnon. From this separation of the valves he finds it 
dimcult to determine to what species these fossil remains belong but 
conjectures rtiat it is to C. octovalvis. I am happy in possessing a 
y pcrec specimen of the fossil testaceous covering of this animal 
rom ngnon, and in its confirming the opinion of M. Lamarck, as 
to the number of its valves, which are eight. 
This fossil is in so high a degree of perfection, as to have made me 
at one time suspect its being only decomposed by exposure to the 
air; but an examination with a lens showed not only the adherent 
matrix, but two species of extremely minute fossil serpul® fixed on 
its convex surface. This fossil is represented Plate V. Fig. 5 and 
by its side are sketches of the minute adherent serpuke. 
Lamarck, adopting certain constant characters, which seem to 
VOL. in. 
H 
