microstomidæ

from The Century Dictionary.

• In ichthyology, a family of malacopterygian fishes, typified by the genus Microstoma, containing a few deep-sea fishes related to the argentines and smelts. Also Microstomatidæ
• A family of rhabdocœlous turbellarians, typified by the genus Microstoma, having a small extensile mouth near the anterior end of the body, together with laterally ciliated pits.