156 CONCHOLOGY. 



Shell wide, rough, oval, spire very short, not projecting ; 

 aperture very large, oval, effuse, sloped anteriorly ; the edges 

 united ; the right or external very thick, dentated ; the two 

 teeth which limit the slope are a little larger than the others ; 

 muscular impression visible, and almost in form of a horse- 

 shoe ; operculum horny and rudimentary. 



C. Peruvianus. The Peruvian Concholepas. PI. 28, 

 fig. 1. 



The type of this genus; exterior dark brown, interior 

 white. 



7. Harpa. The Harp Shell. Eight species. 

 This genus of shells is truly beautiful ; it was classed by 

 Linnaeus with the Buccinum, but Lamarck considered that 

 they were, for their beauty, worthy of forming a genus by 

 themselves. 



Shell oval, inflated, rather thin, with longitudinal parallel 

 ribs, formed by the preservation of the thickening of the 

 right margin ; the spire very short, pointed, the last -whorl 

 much longer than all the others together; aperture large, 

 ovate, widely notched anteriorly; the right edge much ex- 

 cavated and thickened outwardly ; the columella smooth, and 

 terminated in a point anteriorly. 



Harpa imperialis. Harpa articularis, 



H. ventricosa. H. rosea. 



H. conoidalis. H. minor. 



H. nobilis. H, striata. 



H. imperialis, The imperial Harp. 



Species in which the number of ribs far exceeds that of 

 any other, and occasions it often to be called the many-ridged 

 harp ; a small spiral keel round the summit. A rare and 

 valuable species. 



H. nobilis. The noble Harp. PI. 29, fig. 2. 

 A regular species. 



