126 PTEROCERA. 



anterior median fascicle in place of the normal single fasciole ; 

 posterior digitation with an elongated lobe at its left base ; 

 lateral digitations straight or little curved ; all the digitations 

 open, channeled ; wrinkles within the labrum prominent, on the 

 labium faint, often obsolete anteriorly ; aperture whitish or 

 orange-stained, violaceous only within the throat. 

 Length, 4-5 inches. 



Indian Ocean, Zanzibar. 



Undetermined Species. 



P. YOLDII, Morch. Hab. unknown. 



P. ROBUSTA, Swains. Hab. unknown. 



Section II. HARPAGO, Klein, 1753. 



P. CHIRAGRA, Linn. PI. 10, fig. 13. 



Angular fasciole or revolving .rib tuberculated, the others 

 almost unarmed, the antesinual with a compressed tubercle near 

 the base of the digitation ; lips rosaceous, with faint wrinkles ; 

 sutural digitation with a canal open at base, the outer border 

 being bent outwards and attached above the angle of the body- 

 whorl, on which the digitation is chiefly bent and accumbent. 



Length, 6-10 inches. 



Indian Ocean, Philippines, N. Caledonia, Polynesia,. 



P. Kochii, Freyer, is a synonym. 



P. RUGOSA, Sowerby. PI. 10, fig. 12. 



Revolving fascicles except the sutural and anterior with prom- 

 inent tubercles ; lips with very prominent, often white wrinkles 

 strongly contrasting with the deep purplish or blackish ground- 

 color; basal posterior digitation with its canal closed by the 

 reflection of its margins, and accumbent on the middle of the 

 spire. Length, 5-7 inches. 



Zanzibar, Society Islands, etc. 



Probably only a variety of the preceding species. It is P. 

 chiragra, Lam., in part, and P. arthritica, Morch. 



