Actually, in bivalves rostrations are posterior, when a shell is pointy
towards the back, This suggests the presence of siphons, though not
invariably.
Dr. David Campbell
"Old Seashells"
Department of Geological Sciences
CB 3315 Mitchell Hall
University of North Carolina at Chapel Hill
Chapel Hill NC 27599-3315 USA
[log in to unmask], 919-962-0685, FAX 919-966-4519
"He had discovered an unknown bivalve, forming a new genus"-E. A. Poe, The
Gold Bug