tooth which characterizes the Pandora? ; it differs also from them in havin°- a sinus in the 

 muscular impression of the mantle, and in being- possessed of a small testaceous appendage 

 attached to the ligament. 



PANDORA GENERIS CLAVIS ANALYTICA. 



j \ lamina submarginali in valva dextrali conspicua 4 



( lamina submarginali in valva dextrali nulla 2 

 - \ test a postice angustiore 3 



( testa postice dilatata ••••••......,.. 1 obtusa, 



„ \ oblonga, margine superiore subarcuato, recurvo . . . . . . ■ , _ 2 rostrata. 



I elongata, margine superiore rectiusculo 3 oblonga. 



. $ testa postice dilatata. ................. 4 depressa. 



(_ testa postice sequali vel angustiore 5 

 5 ^ testa posticd sequali 5 gl ac ialis. 



(_ testa postice angustiore 6 

 „ ^ testa subventricosa 6 flexuosa. 



{ testa depressiuscula 7 



( postice subrostrata, margine superiore postico rectiusculo 7 Unguiculus. 



( postice rostrata, margine antico superiore alato . . . . . . . . . . 8 nasuta. 



PANDORA OBTUSA. Fig. 1 to 3. 

 Leach, MS. ined. Lam. Anim. sans vert. V. 499. 

 P. testa latere poslico elongato, dilatato ; margine superiore recto, dente in valvd planulatd minimo; long. t \, lat. T V, alt.^%, 

 poll. 

 Hah. in Mari Britannico, juxta litfora. 



Desc. Shell ovate, anterior side very short, slightly angular at the upper part, and rounded beneath, narrower than the 

 posterior, which is much lengthened and dilated ; the upper posterior margin is nearly straight and angular at the end ; upper 

 edge of the flat valve lapping over the concave valve. 



Formerly described and figured by Pennant as a new and singular Mytilus found near Weymouth : it occurs rather rarely all 

 along the south-western coast of England. 



PANDORA ROSTRATA. Fig. 7 to 9. 



Lam. Anim. sans vert. V. 498. 

 P. testd oblong d, latere postico elongato, obtusissime bicarinato ; dcnte unico in valvd planulatd parvo, retuso ; margine supe- 

 riore subarcuato recurvo ; long. l T \, lat. -fo, alt. -fc, poll. 



Syn. Pandora margaritacea, Lam. 



Tellina ineequivalvis, Linn. 



Hab. in Mari Britannico, juxta littora. 



Desc. Shell thin, oblong, posterior side elongated, with two very obtuse keels near the upper edge, somewhat beaked, 

 and slightly truncated ; tooth in the flat valve small and blunt ; hinge margin slightly arched, recurved. 



Common on the shores of Guernsey, Jersey, and Normandy ; occasionally dredged at Weymouth, with the P. obtusa of Leach, 

 from which it is distinguished by its posterior side being narrower and rather beaked. 



PANDORA OBLONGA. Fig. 10. 

 P. testd elongate, latere postico svlrostrato, margine superiore rectiusculo, dcnte in valvd planulatd ligt.mevtoque minimis ; long. 

 1 T V, lat. T %, alt. J„, poll. 

 Desc. Shell proportionally longer than P. rostrata, thin, the posterior side rather beaked, with two very obtuse keels, and 



