The Collaborative International Dictionary of English v.0.48:

Paleocarida \Pa`le*o*car"ida\, n. pl. [NL., fr. Gr. palaio`s
   ancient + kari`s, -i`dos, a kind of crustacean.] (Zool.)
   Same as Merostomata. [Written also Pal[ae]ocarida.]
   [1913 Webster]