Florida Nodilittorina
Littoraria appears to be a genus.  I Googled the name and found this as one of the choices.  http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=567035
 
Re: your second question - same place, ITIS    http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=70394


From: Olivier Caro [mailto:[log in to unmask]]
Sent: Tuesday, October 25, 2005 12:31 AM
To: [log in to unmask]
Subject: Re: Florida Nodilittorina

By the way, what is the level-value of Littoraria : genus, subgenus ?
And, more generally...
Any reliable resource somewhere regarding the syst. of Littorinidae ? (pdf, html, doc, xls...)
 
Cheers
 
Olivier Caro