sii. CONCHYLIA— DJTHFiJJ. 



44i yLoBlOhA.—-Testa suhlongitudinalis, umboiiihus subtermualibus. 



Shell somewhat longitudinal, with the beaks 



nearly terminal. 

 49. Pinna. — Testa cuneiformis, apice dilatato hiante. 



Shell wedge-form, dilated and open at the top. 



47. Lima. — Testa hasi auriculatd. 



Shell with auricles at the base. 



** Car do dentibus primariis, later alibus nullis. 



Hinge with primary teeth, but no lateral ones. 



25. SoLEN. — Testa transversim linearis, cardine subterminali. 



Shell transversely linear, with the hinge near 



the end. 

 43. Mytilus. — Testa longitudinalis, umbonibus terminalibus rectis. 



Shell longitudinal, with the beaks terminal and 



straight. 

 3. GastrocHjENA. — Testa hiantissima, dentibus obsoletis transver- 

 sim lamellosis. 



Shell very open, with the teeth obscure and 



transversely laminar, 



48. AviCDLA. — Testa basi transversim caudatd. 



Shell with a transverse projection at the base. 



