Source : Webster's Revised Unabridged Dictionary (1913)

Mysis \My"sis\, n. [NL., fr. Gr. ? a closing of the lips or
   eyes.] (Zo["o]l.)
   A genus of small schizopod shrimps found both in fresh and
   salt water; the opossum shrimps. One species inhabits the
   Great Lakes of North America, and is largely eaten by the
   whitefish. The marine species form part of the food of right
   whales.

Source : WordNet®

Mysis
     n : type genus of the family Mysidae [syn: {genus Mysis}]