BIVALVE SIIELLS. 281 



14. PisuM Canariense. 



P. testa ovali, coinpressiuscula, valde infcquilaterali, subtiliter 

 striata, sordide albida, pellucida, umbouibus vix prominulis, 

 obtusis. 



Pisidium Canariense, Shuttleivorth, Diagn.neutr Moll.woA .\). 12. 



Hnb. TeuerifFa. 



15. PlSUM ferrugineum. B.M. 



P. testa ovato-rhoraboidea, subcompressa, tenui, cornea, ferri 

 oxydo obtecta. ina;quilaterali, transversim striata ; extremitate 

 antica brevi, rotundata, postica latiore, oblique subtruncata ; 

 apicibus acutis prominulis; dentibus lateraliljus valvula^ dex- 

 triB prominentibus, antico acuto; superficie interna pallide 

 violaceo-ferruginea. 



Pisidium ferrugineum, Krauss,Sudafr.Moll. p./. no.2. pl.l. f. /• 



Hab. Caput Bonje Spei in fluvio Knysna. 



3. Americce septentrionalis. 



16. PlSUM VIRGINICUM. 



P. testa minima, rotundata, subtiliter transversim striata, antice 

 rostrata (Gmelin). 



Pectunculus perpusillus, Lister, Conch. pl. 159. f. 15. 



Petiv. Gazoph. p. 1. ])1. 104. f. 5 (raalus). 

 Tellina virginica, Gmel. Syst. Nat. p. 32.36. no. 39. 

 Tellina pusilla (ex parte), Dillw. Cat. i. 106. no. /6. 

 Cyclas virginica, Ferussac, Observ. Mag. de Zool. 



Hab. Respublica Virginiffi, Araericai septentrionalis. 



17. PlSUM MINUS. 



P. testa rainima, ovata, iria^quilaterali, natibus turaidis, approxi- 

 raatis ; raarginibus rotundatis ; dentibus oranibus crassis. 



Cyclas minor, Adams 8f Migh. Boston Journ. of Nat. Hist. 1842, 

 ■p. 3;^. ]d. 4. f. 2. 



Migk. Cat. oftheShells of Maine, Bost. Journ. of Nat. Hisf. 

 iv. 319. 



Hab. In aquis dulcibus circa Stonington, Respublieae Unitae 

 Americ.x septentrionalis. 



18. PlSUM ABRUPTUM. 



P. testa ovata, valde inicquilaterali, olivacca vcl jiallide castanea ; 



