VI APPENDIX. 



794. FISSURELLA APERTA. 



r. testa ovati, carne<^, fusco-radiatA, margine Inte- 

 gra, alba, depi'essa; foramine ovato, magno : long. 

 1 unc. lat. I unc. 



Ohs. There are two specimens of this shell, 

 which is easily distinguished by its large ovate, en- 

 tire foramen, independently of the depressed white 

 margin, which is probably caused by the mantle of 

 the animal overlapping the edge of the shell. 



795. FISSURELLA CLYPEIFORMIS. 



F. testa ovato-oblong^, depressiuscuM, laevi, extus 

 fusc4; foramine elongato, intus integro, extus la- 

 teribus coarctatis, utrinque unidentatis ; margine 

 uudulati^ infra albida; long. 2^*^ unc, lat. 1,V 

 unc. 



796. FISSURELLA CRENULATA. 



F. testa oblongo-ovatd, depressa, alba; foramine ova- 

 to, integro ; superticie striis confertis, radianti- 

 bus, decussatis; margine crenulata ; long. Sj^^unc. 

 lat, 2^'^ unc. 



Obs. Besides these three undescribed species 

 there are the six following, viz. Nos. 797 to 802, which 

 do not appear to be mentioned by Lamarck, yet we 

 have not ventured to describe them, on account of 

 the extreme difficulty of ascertaining whether or not 

 they are already noticed. 



808. SIPHONARIA GIGAS. 



S. testa suborbiculari, conic^, radiatim carinato- 

 costata, costis distantibus; vertice recto, centrali: 

 long. 2i^ unc. lat. 2 unc. 



Obs. Tliis is the largest species of the genus we 



have seen : from Panama. 



