PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM issued p^?(V>4. mIMb ^y '^^ SMITHSONIAN INSTITUTION U. S. NATIONAL MUSEUM Vol. 101 Washington: 1951 No. 3272 THE OCEANIC CRABS OF THE GENERA PLANES AND PACHYGRAPSUS By Fenner a. Chace, Jr. On September 17, 1492, at latitude approximately 28° N. and longitude 37° W., Columbus and his crew, during their first voyage to the NevT World, "saw much more weed appearing, like herbs from rivers, in which they found a live crab, which the Admiral kept. He says that these crabs are certain signs of land . . . "(Markham, 1893, p. 25). This is possibly the first recorded reference to oceanic crabs. Whether it refers to Planes or to the larger swimming crab, Portunus (Portunus) sayi (Gibbes), which is seldom found this far to the east, may be open to question, but the smaller and commoner Planes is frequently called Columbus's crab after this item in the discov-erer's diary. Although these crabs must have been a source of wonder to mariners on the high seas in the past as they are today, the first adequate description of them did not appear until more than two centuries after Columbus's voyage when Sloane (1725, p. 270, pi. 245, fig. 1) recorded specimens from seaweed north of Jamaica. A short time later Linnaeus (1747, p. 137, pi. 1, figs. 1, a-h) described a sunilar form, which he had received from a Goteborg druggist and which was reputed to have come from Cantou. This specimen, which Linnaeus named Cancer cantonensis, may be the first record of the Pacific Planes cyaneus. The Atlantic species, found "in Palgi Fuco natante," was finally described under the name Cancer minutus by Linnaeus in the tenth edition of "Systema Naturae" (1758, p. 625). Bowdich (1825, p. 15, pi. 12, figs. 2, a-h) briefiy described and figured a crab found on a floating log northeast of Madeira as Planes clypeatus. 874803—51 1 65
BioStor
