Passively & actively filled

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Is the spherical, (sub)vertical, unbranched burrow with an active and passive filling lined or does it have a mantle? Please, choose accordingly:

  1. With lining/mantle
  2. Without lining/mantle

Take me to the ichnology start page!

Take me back to the beginning of the determination key!

Take me to the alphabetical list of ichnogenera!

[Passively & actively filled]