cavicornia

from The Century Dictionary.

• The hollow-horned ruminants considered as a family or other zoölogical group of mammals, contrasting with the solid-horned ruminants, or deer, Cervidæ.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) A group of ruminants whose horns are hollow, and planted on a bony process of the front, as the ox.