The Collaborative International Dictionary of English v.0.48:

Regularia \Reg`u*la"ri*a\ (r[e^]g`[-u]*l[=a]"r[i^]*[.a]), n. pl.
   [NL.] (Zool.)
   A division of Echini which includes the circular, or regular,
   sea urchins.
   [1913 Webster]