No. XL— MARINE BKACHYURA. By Mary J. Rathbtjn, Assistant Curator, Division of Marine Invertebrates, United States National Museum, Washington, U.S.A. (Plates 15—20 and Text-Figures 1, 2.) (Communicated by Prof. J. Stanley Gardiner, M.A., F.R.S., F.L.S.) Read 2nd February, 1911. The collection of crabs is a large one, comprising 245 species and subspecies ; of these, 33 species and 3 subspecies are new to science, and for 3 of the species new genera are constructed. The majority of the previously described species are entered in the works by Alcock, Laurie or Borradaile on the Brachyura of India, Ceylon and the Maldives, or form part of the Indo-Pacific fauna. Among the exceptions are three species from the Seychelles which have been recorded hitherto only from the Red Sea, or Persian Gulf, or both, viz. : Atergatopsis signata, Actumnus bonnieri and Eumedonus granulosus. Another Red Sea form, Actumnus globulus, was taken by the " Sealark " at the Chagos Archipelago. The results of the expedition show no connection with the West African fauna. The genus Callinectes, it is true, is found for the first time in the Indian Ocean. This genus reaches its greatest abundance both as to species and individuals, in temperate and tropical America, and is fairly abundant on the west coast of Africa. The Indian species, however, is similar to, if not identical with, that lately recorded from the " Albatross " collection in the South Pacific. Most numerous among the "Sealark" crabs are the small oval Xanthids, as Aetata, Carpilodes, Pilumnus, etc. To the same family belongs a new and widely divergent type with a stridulating mechanism, which has been named Gardinena in honour of the leader of the expedition. A different arrangement for producing sound is presented by a new species of Marietta; it is the first occurrence of the sort noted among the Palicidaj. There is an entire absence of Pinnotheridse and, save for one species of Typhlocarcinops, of those hemispherical forms of the Gonoplacidte which were so abundant in Dr Mortensen's collection in the Gulf of Siam'". * K. D. Vidensk. Selsk. Skr., 7 R., n.— m., Afd. v. 4, 1910, pp. 303—368, text-tigs. 1-44, pis. 1-2, 1 map. SECOND SERIES— ZOOLOGY, VOL. XIV. 25
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