(biology) Of or pertaining to something at its lowest point; designating the part opposite to the apex.
- 1946—Cushman, Joseph A. (1946). Upper Cretaceous Framinifera of the Gulf Coastal Region of the United States and Adjacent Areas. Professional Paper 206. Washington, D. C.: U. S. Department of the Interior, Geological Survey. p. 70 – via Google Books.
The deck, which is not far below the aperture, has a narrow indentation on the abapical side and a wider indentation on the adapical side.
- 1973—Henderson, R A (March 1973). "Clarence and Raukumara Series (Albian—?Santonian) Ammonoidea from New Zealand". Journal of the Royal Society of New Zealand 3 (1): 86. Retrieved 3 February 2016 – via Google Books.
The two abapical rows of tubercles of available specimens show a complete range of variation from completely separated to almost completely coalesced.