Dear Steve,
 
Your species number 7 is probably Macron aethiops (Reeve, 1847), a species
"common on the outer coasts of Baja California, rare in the Gulf of
California" according to Keen (1971, Seashells of Tropical West America).
Check also the nice revision of the genera of Pseudolividae (family that
includes the genus Macron) published by G. Vermeij (1998, Generic revision
of the neogastropod family Pseudolividae, The Nautilus 111(2):53-84.)
 
Regards,
 
__________________________________________________________________________
Jose H. Leal, Ph.D.
Director, The Bailey-Matthews Shell Museum
Editor-in-chief, THE NAUTILUS
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3075 Sanibel-Captiva Road
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(941) 395-2233; fax (941) 395-6706
 
"But fit the facts together in any other way and you get more nonsense
instead of less." -- Travis McGee