— 20 — 

 Gcnus Dohax, L. ct Laink. 



D. trunculus, L. 



D. semistriata, Polii. Not coramon. 



D. venusta, Polii. (A variety of the preceding ? Xobis.) 



D. complanata, Mout. Yery rare. 



Gcnus Mesodesma, Deshayes. 



M. donacilla, Desh. Rare. 



Gcnus Astartc, Sowb. 

 A. incrassata, Brocchi. Somewhat rare. 



IX. Fataiilia COXCILE, Lanik. 



Gcnus Pisidium, Pfeiffer. 



P. fontinale ? , (Cyclas) Drap. In stagnant wator at the 

 Marsa, and in fountains. 



Gcnus Cytherca, Lamk. 



C. chione, L. Piare. 



C. rudis, (Venus) Polii ; syn. C. venctiana, Lamk. Com- 



mon. 

 C. cyrilli, Scacchi ; Varictatcs -plurcs; syn. C. apicalis, 



Phil. vol. i. More frequcnt than the prcccding. 

 C. lincta, Lamk. With a variety. At present rare. 

 C. exoleta, L.*, syn. Artemis exoleta, Polii. Freruient. 



Cythercce fossilcs. 



Casts of Cytherea, not yet perfectly known, are found in Bcd 

 No. 1, the coralline limestono. (T. Wright). 



