Limotheres, a new genus of Pinnotherid crab, commensal of the Bivalve Lima, from the Caribbean sea

During the 1970 Caribbean cruise of R.V. "John Elliott Pillsbury" of the University of Miami, a peculiar Pinnotherid inhabitant of Lima tenera Sowerby was collected. Recognized on board as something unusual, it was later found to belong to an undescribed genus and species. I want to express here my sincere gratitude to Drs. Gilbert L. Voss and Frederick M. Bayer of the Rosenstiel School of Marine and Atmospheric Science, University of Miami, for permitting me to join this "Pillsbury" cruise and for allowing me to study this interesting specimen. The abbreviations cl. and cb. stand for carapace length and carapace breadth, respectively. Limotheres new genus Definition. — The carapace is ill-calcified, but rather firm. It is bluntly quadrangular or hexagonal in outline and shows a striking triangular blunt rostrum. It is about as long as wide, being widest in the posterior third. A high post-frontal ridge extends over the full width of the carapace; before this ridge the surface of the carapace drops abruptly down. Three deep longitudinal grooves cut across the ridge. The surface of the carapace is smooth and even. No regions are defined. The orbits are small and placed at either side of the base of the rostrum. The eyes are immovable. The antennulae are folded lengthwise. The antennae are very short, the flagellum consists of a few segments only. The epistome is distinct. The buccal cavity is trapezoid, being much wider than long, and widest posteriorly. The cavity is completely closed by the third maxillipeds, which are placed almost transversely. The ischium and merus of the third maxilliped are fused. The palp is very much shorter than the merus