8 
LETTER II. 
ECHINITES ARRANGEMENT OF LESKE ADOPTED THE VARIOUS 
SPECIES OF THESE FOSSILS DESCRIBED ANOCYSTI, DIVIDED INTO 
CIDARES AND CLYPEI. 
The next subjects of our inquiry are the fossil substances termed 
Echinites, the mineralised remains of the echinus ; an animal of a 
roundish form, covered with a bony crust, approaching nearer to the 
coverings of the crustaceous than to those of the testaceous animals, 
and furnished with moveable spines ; the mouth being placed beneath. 
The characters of many of these bodies are so remote from each 
other, as to seem to point out the propriety of considering the whole 
as forming a distinct order of vermes, thus marked out as different 
genera, possessing other characters, which would well serve for the 
distinction of species. 
Many have endeavoured to bring the incongruous assemblage in the 
Linneean genus, echinus, into a more lucid and instructive arrange- 
ment. To this work the labours of Muller, Phelsum, Bruguiere, and 
Lamarck, have much contributed : but to no one is more merit due, 
in this respect, than to the industrious Leske, the ingenious commen- 
tator on Klein’s useful work. It is intended, in the following pages, 
chiefly to be aided by the arrangement of Leske, who has also availed 
himself of the labours of Phelsum and of Muller. 
Agreeable to this arrangement, the first class of these bodies which 
we shall examine is that of the Anocysti, the vent of which is in the 
