inframedian

adjective2

1. •
   Of or relating to the interval or zone along the sea bottom, at the depth of between fifty and one hundred fathoms.

   • The inframedian zone ranges from fifty fathoms to a hundred. — 1853
2. •
   Below the middle.

   • Thus the upper, inframedian and carinal laterals have three layers, but the rostrum and rostro-laterals, which appear at a later stage, have only two. — 1930