leptocardian

from The Collaborative International Dictionary of English v.0.48

Leptocardian \Lep`to*car"di*an\ (l[e^]p`t[-o]*k[aum]r"d[i^]*an),
   a. (Zool.)
   Of or pertaining to the {Leptocardia}. -- n. One of the
   Leptocardia.
   [1913 Webster] Leptocercal