gerontic
/dʒɛˈrɒntɪk
/adjective
Relating to old age, elderly people, or senescent animals or plants.The gerontic whorl of gastropod genera of the subfamily Mitchelliinae is twisted both outwards and backwards, but not upwards as in members of the subfamily Scoliostomatinae....
- Rapid growth of the inner and basal parts of the apertural margin during their late shell ontogeny caused twisting of the gerontic whorl both outwards and backwards.
- The gerontic aperture is narrowly elongated in species of Eoscoliostoma, but rather circular in Scoliostoma species.
Origin
Late 19th century: from Greek gerōn, geront- 'old man' + -ic.