254 
The Natural Hiftoryof JAMAICA. 
Cracv. IX. 
Of the Coverings for the Mouths of fome anknowa Shells, 
I. Perculum, five umbilicus marinus hemi[phericus, albidus, levis. Tab. 
241. Fig. 1. | 
This was flat on one fide, hemifpherical on the other, about haif an 
Inch Diameter, all white only onthe upper part of the Hemifpherc it 
was brownifh. It wasall fmooth, and had a vifible fpiral Line on the 
flat fide which is on the out fide ofthe Mouth of the Shell. 
I found it on the Shores of Famaica, and have received it gather’d up 
on the Shores of the Magellan Streightsby Mr. Hanayfide. 
II, Opercalum, five umbilicus marinus apicibus parte convesa donatus, gib- 
bofus, oblongus, Tab, 241. Fig. 2: 
This was oval, an Inch long, and about three quarters of an Inch 
broad, flat on. one fide, rais’d and hemifpherical on the other, where 
were abundance of fmall round Apéices or extant white Points. ‘T'he 
flac under Part was brown, and had a fpiral Line on it. 
It was fent from amaica to Mr. Petiver who gave it to me. 
III. Operculum, five umbilicus marinus e viridi nigricans, compreflus, men- 
branaceus. Tab. 241. Fig. 3- 
This was ho thicker than a Membrane of a horny Subftance, perfectly 
flat without any Rifing or Convexity of either fide. It was of a greenifh 
black Colour near an Inch Diameter and had a fpiral Line upon it. 
I had it from, Famaica, 
ro 
bial 
GimaAr. 
Of Bivalv’d Shells, and first of the Pinna, and Spond yi. 
I.) lv tenuis Papp ae Lik. Htst. Conchyl. Tab 370. N°* ‘215. 
Pinna lata altera. Rumph, Tab, 46. lit. M. 
The {mall muricated Pinna. 
This Psana is about half a Foot or fix Inches long, beginning at 
the Cardo very fmall, and growing broader to the roundifh wide 
End. Ie is ftriated on one half by coundifh or circular Strie, and on 
the other by extant Ribs, which towards the broad End are muri- 
cated or have hollow pices. The whole Shell is of a greyifh brown 
Colour and very thin. | 
‘Flitre are fome of thefe Shells not half fo big, and others not muri- 
cated, which perhaps are only Varieties from Age or Accidents. 
I found them plentifully caft upon the Shores of Famaica by the Sea. 
iI. 
