nasal sacs

na·sal sacs

the deepened nasal pits that develop into the definitive nasal cavities.

na·sal sacs

(nāzăl saks)
Deepened nasal pits that develop into definitive nasal cavities.
References in periodicals archive ?
Scientists theorize that orcas force air between the nasal sacs and the blowholes to produce a range of sounds from 0.1 kilohertz to 40 kilohertz.
At an early age each dolphin adopts a personalized call--a unique whistle of rising and falling tones that emanates from nasal sacs below the blowhole (the single nostril atop a dolphin's head).