The Collaborative International Dictionary of English v.0.48:

Sclerobase \Scler"o*base\ (? or ?), n. [Gr. sklhro`s hard +
   ba`sis base.] (Zool.)
   The calcareous or hornlike coral forming the central stem or
   axis of most compound alcyonarians; -- called also foot
   secretion. See Illust. under Gorgoniacea, and
   Coenenchyma. -- Scler`o*ba"sic, a.
   [1913 Webster]