140 



CONCHOLOGY. 



P. bulbus. 



P. cariosa. 



P. Rudolphi. 



P. succincta. 



P. bitubercularis. 



P. haemastoma. 



P. callosa. 



P. callifera. 



P. scalariformis. 



P. rugosa. 



P. textilosa. 

 P. lambosa. 

 P. lapillus. 

 P. cateracta. 

 P. fiscella. 

 P. semi-imbricata. 

 P. deltoides. 

 P. trochlea. 

 P. vexillum. 

 P. distorta. 



P. tectum. 



P. engonata.* P. harpa.* 



P. brevidens.* P. Floridana.* 



P. lapilloidis.* P. dumosa.* 



P. macrostoma.* 



5. Genus JMonoceros. PI. XII. 



Jlnimal. As above. 



Shell. Differs only from the Purpura by a long, conical 

 pointed, somewhat reflexed tooth in the outer lip. Five species. 

 T Monoceros cingulatum. Monoceros striatum. 



M. imbricatum. M. glabratum. 



M. crassilabrum. 



6. Genus Concholepas. PI. XII. 



Jlnimal. Entirely unknown. 



Shell. Wide, rough, ovate ; spire very short ; aperture very 

 large, oval and sloped anteriorly ; the edges united, the right 

 very thick and dentated ; muscular impression almost in form of a 

 horse-shoe ; operculum horny and rudimentary. It was formerly 

 considered a Patella, from which it differs by the operculum. One 

 species. 



Concholepas Peruvianus. 



7. Genus Harpa. PI. XII. 

 Ajiimal. Unknown. 



