The Collaborative International Dictionary of English v.0.48:

Pan- \Pan-\, Panta- \Pan"ta-\, Panto- \Pan"to-\ [Gr. ?, m., ?,
   neut., gen. ?, all.]
   Combining forms signifying all, every; as, panorama,
   pantheism, pantagraph, pantograph. Pan- becomes pam- before b
   or p, as pamprodactylous.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Panto- \Pan"to-\
   See Pan-.
   [1913 Webster]