spheniscidæ

from The Century Dictionary.

• The penguins as a family of squamipennate or brevipennate palmiped natatorial birds, of the order Pygopodes; the only family of Spheniscomorphæ, Squamipennes, Impennes, or Ptilopteri, so strongly marked that it is regarded as representing a superfamily, order, or even superorder, though formerly included in the Alcidæ, or auk family.