m 
felves ^rfc refolved into Utle Shells^ and 
the little Shells into Th’reds, and there h 
the fame difference in the Threds,as allb 
the fame pofition or fcitei That thefe 
Shells Were once the parts of Animals li* 
ving in a Fluid, though there never had 
been fech anyTeftaccoUs Marine Grea- 
tures, the Very view of the Shell it lelf 
evinceth, as may be evident by the In- 
ftance oi Si”valve Cockle*jhells. 
At the time that the Bhvalve Cockle-' 
fliells Were formed, the matter, contain*; 
ed within them, 
I. Had aftnoothfurfaceihaving irinW- 
merable pores, and tvvo different forts df 
pores. 
1. It had a flexile lubfianGe, ^lid leis 
hard than the Shell it felf, 
3. It communicated With the ambi* 
ent matter On onfefidej buthad no cpm- 
merce With it on the Otheir; 
4. It'did by little and little tecedO 
from that fide, where the Communica¬ 
tion with the external matter Was deni¬ 
ed it, towards that fide,where it had that 
commerce -with the fame matter free* 
5. It hath been able by intervals to 0- 
pen it ielf according to the widcnefs of 
the 
