lj6 
WORMS. TESTACEA. 56. Mya. 
Inhabits frefh rivers of 2) Barhary, 6 ) Tfanquebar, , 
is the fhell which is commonly ufed to put water colours 
t| inch long, 3! broad; covered with a brownii'h or black'*^ 
coat, and under this yellowiih or greenilh, wirli green raf j 
within fmooth and clay-colour : very thin and brittle, 
docs not gape at either end. 
• Margari- Shell ovate, a little contraiSed in the middle of the thino*^ 
t’/era, margin ; primary tooth of the hinge conic : protub*' 
rant parts near the hinge decorticated. 
Brit. Zool.hf tab.^l,f. 1 8. Barbut, tab, z,f, 2. 
Lifter conch, tab. 149, fig. 4. 
Lifter Anim. Angl. afp. tab. 1 , fig. l . 
Gualt. tab 102, Jig. C. Klein, tabi lo, /. 47. 
Knurr. Kergn. 4. tab. 2J, fiig, 2. 
Chemn. conch. 6. tab, l. fig. 5. 
Inhabits moft parts of the ArAic circle, and is generally found 
mountainous rivers and ab mf cataratb ; about 5 inches bros 
and 2i tong : /hell thick, coarfe, opakc, tranfverlely wrinki**’ 
black, on the outfide, and often corroded by worms; hi 4 ‘ 
without lateral teeth, the primary tooth being received in^® 
broad cleft tooth of the oppofite hinge. t 
This fhell is noted for producing large quantities of mother ® 
pearl and pearl, thefe latter being a difeafe of the filh analf' 
gous to the ftone in the human body. The river Convray 
U'^ales was formerly famous for producing pearl of great f'*'' 
and value. 
Perna. Shell oblong, dilated, the narrower bafe compreffed. 
Knorr. I'ergn. 4. tab. rj, fig. 2, 4, 5. 
Chemn. conch. 8 tab. 83, f 738, 739. t. 84, f. 748, 
Schract. Einl. conch. 2. tab '],fig> 4. 
Inhabits the Magellanic Straits and Ihores of Barbary ; refcmbl*^ 
a ham or leg of mutton ; Jhell fmooth, blue and white, ope® 
one end : inOead of the hi'ge is a deep tranfverfe hollotv, 
the middle of which is a fharp tooth in each valve : probabu 
not of this Genus. 
Kulftlla. Shell tongne-lhaped j the hinge terminal, depreffed 
femiorbicular. 
Lijier conch, tab. lOJJ.y. 10. 
Rump/. Muf, tab, 46. ftg. A. Gualt. tab. 90. f. H. 
Kalent. Mufi. tab. 16. fig. 28. Barbut. tab. z.fi, 3, 
Knorr, Vergn. 3. tab. 1 , fig. I — 3. 
Chemn, conch, 6. tab. 2 . fig. 8—1 1. 
Inhabits the /«<//«.- li inch broad, 4 inches long. 
Shell varying in form according to its age; the rather 7®' 
gaping, finely ftriate tranfverfely, outwardly yellowiih rad>* . 
with blackilh and yellowiih ; tooth long, broad and gro®'' 
along the middle : probably not of this Genus, 
