i ? 6 WORIVtS. TESTACEA. 56. Mya. 



Inhabits frefh rivers of Europe, 2) Barbary, 6)Tranquebar, ani 

 is the fhell which is commonly ufed to put water colours in: 

 if inch long, 3^ broad ; covered with a brownifh or blackifli 

 coat, and under this ycllowifh or grrenifh, with green rays; 

 within fmooth and clay-colour: very thin and brittle, and 

 does not gape at either end. 



* Margari* Shell ovate, a little contracted in the middle of the thinner 

 tfera, margin : primary tooth of the hinge conic : protubc* 



rant parts near the hinge decorticated. 



Brit. Zool.'vi tab.^,f 18. Barbut, tab. l,f 2* 



Lifter concb. tab I49, Jig. 4. \ 



Lifter Anim. Angl. app. tab. 1, fig. I. 



Gualt tab 102, fig. C. Klein, tab. io, f. 47. 



Knorr. Vergn- 4. tab. 25, fig, 2. 



Chemn. concb 6. tab, I. fg. 5. 



Inhabits moil parts of the Arclic circle, and is generally found M 

 mountainous rivers and about cataracts ; about 5 inches broad 

 and z\ long : Jbell thick, coarfc, opake, tranfverfely wrinkled; 

 black on the outfide, and often corroded by worms: hinge 

 without lateral teeth, the primary tooth being received into a 

 broad cleft tooth of the oppofite hinge. 



This (hell is noted for producing large quantities of mother of 

 pearl and pearl, thefe latter being a difeafe of the nfh analo- 

 gous to the (tone in the human body. The river Conway in 

 Wales was formerly famous for producing pearl of great fize 

 and value. 



^ 



Pjtna. Shell oblong, dilated, the narrower bafe compreffedi 



Knorr. ("erg ft. 4. tab. I c, fig. 2, 4, 5. 



Chemn. conch. 8 tab. 83, f 738, 739. /. 84, f. 7484 



Schrcet. Einl. conch. 2. tab. J, fig* 4. 



Inhabits the Magellanic Straits and mores of Barbary j refembleS 

 a ham or leg of mutton : fhell fmooth, blue and white, open at 

 one end : infead of the hinge is a deep tranfverfe hollow, in 

 the middle of which is a fharp tooth in each valve : probably 

 not of this Genus. 



fAjlfella, Shell tongue-fhaped ; the hinge terminal, deprefTed and 

 femiorbicular. 



Lifer conch, tab. lo$$.f. 10. 



fcumpf. Muf. tab. 46. fig. A. Qualt. tab. 90. /. H. 



Valent, Muf tab. 16. fig. 28. Bar but, tab* 2./. 3. 



Knorr. Vergn. 5. tab. 2., fig* I — J* 



Chemn. conch, 6. tab, 2, fig* 8-— I 1. 



Inhabits the Indies: if- inch broad, 4 inches long. 



Shell varying in form according to its age : the <valves rather flat, 

 gaping, finely ftriate tranfverfely, outwardly yellowifh radiate 

 with blackifh and yellowifh: tooth long, broad and grooved 

 along the middle : probably not of this Genus* 



