Noun
A blind tube branching out of a longer one.
Source: Webster's dictionaryAlthough many fish are capable of hearing, the lagena is, at best, a short diverticulum of the saccule, and appears to have no role in sensation of sound. Source: Internet
The pharyngeal opening of each diverticulum is soon obliterated, but the neck of the flask persists for some time as a cellular cord. Source: Internet