C 401 ] 
proportionable ThicknefTes, concludes tLchini of a 
vaft Bignefs, to have a Number of fuch Spines to 
move* 
The Varieties of the Belemnites , how can they 
quadrate to the Spines of one Genus of Echini only ? 
Solid Belemnites , Belemnites with a fingle Cruft* or 
like a Tube, with a conic Cavity only 5 that empty, 
or otherwife filled with a folid Mafs, or with a re- 
gular jointed Body* as th z Alveolus Belemnites 
of various Magnitudes and ThicknefTes, &c. can all 
thefe Varieties be imagined to belong to one Genus 
of Shells, which we fuppofe to exift to maintain a 
favourite Syftem > 
The Number of Species of Echini difcover’d are 
numerous j and the Spines of all thofe agree in 
having a hollow Axis , which runs proportionably 
from their Bafis to their Apex , quite different to 
the Belemnites : And for their Conftitution, a fo- 
reign Nat ura lift, a Member of the Royal Society , 
Mr. Klein of Dantzick , who has profefledly 
wrote on this Subject, could only find of two Kinds, 
<viz. thofe of a porous Conftitution, which he ob- 
ferved only to belong to one Genus 5 and thofe of 
a folid fhattery Subftance, like a talcy Spar not; 
ftriatech, which is the moft general, and is exa&ly 
the fame Conftitution as all the foflil Spines, or 
Lapides Judaici are. 
Further, the Lapides judaici have, at fome times, 
been found adhering to their BapilU or Tubercles, 
and with Fragments of their Shells 5 whereas no 
Naturalift has ever known to be found foflil either 
the Shells, or the Fragments of fuch a Genus of 
Echinus * not even any Remains proportionable to 
E f f 2 fuch 
