Abstract
The complete larval development of Tiaramedon spinosum (Miers, 1879), an obligate symbiotic crab of comatulid crinoids, is described and illustrated on the basis of laboratory-reared material. It consists of four zoeal stages and one megalop. Zoeas of T. spinosum are readily distinguished from those of other eumedoniine species by the armature on the carapace and bases of the first and second maxillipeds. Morphology of the T. spinosum megalop differs from that of Echinoecus pentagonus and Zebrida adamsi in the shape of the carapace, segmentation of the antennal flagellum, and setation of the second maxillipedal epipod and uropodal protopod.
