SC - Scungilli versus conch

[LrdRas at aol.com]

In a message dated 3/2/00 7:07:10 AM Eastern Standard Time, troy at asan.com 
writes:

<< I'd been meaning to mention this... scungilli are actually knobbed
 whelks, not conch(s?)(es?). Conch(plural) have a shinier, more rounded
 shell, without siphon protuberances, while whelks tend to be more angular. >>

Master,

Source of information, please? In my early years as an 'Italian' professional 
cook the words were used interchangeably. Also the dictionary supports my 
view as noted below:

scun*gil*li (noun)

[Italian dialect (Neapolitan) scuncigli, plural of scunciglio conch]

First appeared 1945

 : conch used as food

Various quick flipping through assorted culinary dictionaries also say they 
are synonymous. Whelks are not mentioned as an alternative for 'scungilli' in 
any of those sources. 

Ras