GENERA OF SHELLS. 



GALEOLARIA. Tubes testaceous, very nume- 

 rous, cylindrical, subangular, raised, undated, 

 grouped, fixed at base, open at summit ; aper- 

 ture orbicular, edge terminating at one side by 

 a tongue. Operculum furnished above with 

 from five to nine pieces attached to the edge 

 by one side. 



G. caespitosa, elongata. 



MAGILUS. Base of the shell convoluted into 

 a short, oval, snail-like spiral ; four contiguous 

 whorls convex, the last largest, and prolonged 

 into an undulated tube. Tube convex above, 

 carinated beneath, slightly depressed and 

 plaited at the sides. Folds lamellar, undu- 

 lated, thicker at one side than the other. 



M. antiquus. 



CLASS X. CIRRHIPEDA. 



Shell sessile, or elevated on a flexible, tendinous 

 pedicle, sometimes movable, sometimes fixed; 

 the inside covered by the mantle of the 

 animal. 



ORDER I. SESSILE CIRRHIPEDA. 



Shells fixed on marine bodies. 

 TUBICINELLA. Shell univalve, operculated, 

 tubular, erect, surrounded with transverse ribs, 



