Source : Webster's Revised Unabridged Dictionary (1913)

Selachii \Se*la"chi*i\, n. pl. [NL., fr. Gr. ??? a fish having
   cartilages instead of bones.] (Zo["o]l.)
   An order of elasmobranchs including the sharks and rays; the
   Plagiostomi. Called also {Selacha}, {Selache}, and
   {Selachoidei}.

Selachoidei \Sel`a*choi"de*i\, n. pl. [NL. See {Selachii}, and
   {-oid}.] (Zo["o]l.)
   Same as {Selachii}.