from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of or relating to a bone between the prootic and epiotic in the dorsal and outer part of the periotic capsule of many fishes.
- n. The pterotic bone.
from the GNU version of the Collaborative International Dictionary of English
- adj. Of or pertaining to, or designating, a bone between the proötic and epiotic in the dorsal and outer part of the periotic capsule of many fishes.
from The Century Dictionary and Cyclopedia
- In zoology and anatomy, noting an ossification of the periotic capsule or petrosal bone, distinct from the proötic, epiotic, and opisthotic, which occurs in some vertebrates between the proötic and the epiotic.
- n. A pterotic ossification. See first cut under teleost and cut under Esox.
- n. Specifically, in fishes, a posterolateral ossification of the cranium.
A third (pterotic) roofs in the tympanic cavity and antrum; while the fourth (epiotic) appears near the posterior semicircular canal and extends to form the mastoid process (Vrolik).