Possible Clues:

• Something very scarce, probably valuable
• That's the way to make oneself scarce - or try to with air
• Fish seen round mouth of river? It's a wonder
• Very unusual occurrence
• I tarry with uncertainty, which is not common
• Hen's tooth, e.g.
• It's seldom that I try to follow the Academician
• That's the Academician I try to make unusual
• Unusual specimen
• I tarry (anag.)