Source : Webster's Revised Unabridged Dictionary (1913)

Malacobdella \Mal`a*cob*del"la\, n. [NL., fr. Gr. ? soft + ? a
   leech.] (Zo["o]l.)
   A genus of nemertean worms, parasitic in the gill cavity of
   clams and other bivalves. They have a large posterior sucker,
   like that of a leech. See Illust. of {Bdellomorpha}.

Bdellomorpha \Bdel`lo*mor"pha\,n. [NL., fr. Gr. ? leech + ?
   form.] (Zo["o]l.)
   An order of Nemertina, including the large leechlike worms
   ({Malacobdella}) often parasitic in clams.