ON MOLLUSCA OF THE WEST COAST OF NORTH AMERICA. 



625 



* The young shell is thin, semitransparent, with Alaboid tuberous vertex. The nuclear 

 partis rather more tumid than the next whirl, and set slanting as in some Chrysodomi. 

 Adolescent, whirls smooth, except a sutural line. Sculpture of adult gradually developed, 

 with spiral lines, sometimes all over, sometimes only anteriorly and posteriorly. Last 

 whirl sometimes with blunt radiating riblets, but generally smooth. Siphonal notch deeply 

 cut back, as in Strombina, to which the species may belong. 



1863. 



