Biological Results of the University of Miami Deep-Sea Expeditions. 74.

Rediscovery of Munidopagurus Macrocheles (A. Milne-Edwards, 1880) (Crustacea, Decapoda, Paguridae), with a Description of the First Zoeal Stage

Material of a genus and species of hermit crab hitherto known from a single female has been taken at widely scattered stations in the tropical western Atlantic. Morphological peculiarities of the genus, particularly the elongated form of the fourth pereiopods, which lack the well-developed rasp usual in pagurids, and a very large spine on the uropodal protopods, have functional significance. The species is not a user of gastropod shells, but an apparently obligate commensal with an anemone, which it carries over its abdomen and back in the fashion of a sack.

The first-stage larva obtained in the laboratory differs significantly from all previously described larvae of the family Paguridae. Certain larval features, particularly the broad spatulate telson, may confirm relationship of M. macrocheles to other genera previously placed together with Munidopagurus on the basis of adult morphology.

Illustrations of morphological peculiarities, of the living anemone and crab, and of the crab larva are included.