( H\ 
an Operculum of a Marine Turben for the true fynguu 0u 
dor at us. 
Take the Hifiory of the Vnguis out" of Diofcorides. c It 
' is found, fays he, in the Lakes of where Narde 
4 grows ; wherefore the Conchy lia feeding on Narde are 
* Aromatick. It is gathered alter that the Lakes are dried 
4 up with the Summer Heats. He concludes, die Ccnchy- 
( Hum it (elf burnt or calcin'd, is of the fame Efficacy 
i with the Purpura and Buccinum burnt in the Chapter of 
< Narde. He fays farther, That the Indian Narde grew 
? near the River Ganges, that is, in certain Lakes, which 
the over-flowing of that River caufed. Hence it appears 
(i) That the Vnguis Adoratus was part of afrejh Water 
Conchylium, (2) Now if it was gathered in the Nardi- 
ferous Lakes upon the River Ganges, how comes it to 
pafs that the fame was brought out of the Red Sea and 
Babylon. And why fliould the Shell it felf be brought, 
an uftlefs Luggage fb far, as from the River Ganges to 
Greece, the Operculum rarely being a Tenth part of the 
Shell it (elf. Now if it was not u(ed to be brought and 
expoftd to Sale, to what purpofe to declare its Vertues, 
or how could the Experiment be made. I conjecture 
therefore, that the true Vnguis Odoratus was fomethirig 
Jike the half oi^feBunculusFluviatilis^ To common in 
the River Thames, of the bignefs and thickneft of my 
Thumb Nail, and that for thele Reafons- 
1. That the Vnguis Odoratus ftems to have been a 
frefli-water Bivalve or Mufcle,for that they ftay'd till the 
Lakes on the River Ganges were dried up before they ga- 
thered them. Now Bivalves are ever buried in Sand 
and Mud, and never rife up and fwim about and float 
as the Turbinate Snails do, to which latter only the 
Operculum belongs, and which therefore were always, 
and eafiiy to be caught. 
K 
2. He 
