1877-] ON CRUSTACEA FROM SOUTH AMERICA. 653 9, On a Collection of Crustacea, Decapocla and Isopoda, chiefly from South America, with descriptions of new Genera and Species. By Edward J. Miers, F.L.S., F.Z.S., Assistant in the Zoological Department, British Museum, [Eeceiyed June 13, 1877.] (Plates LXVI.-LXIX.) The greater number of the Crustacea described in the followin* paper were collected hi Peru, Guiana, Cayenne and Martinique, and were sent by Professor A. Wrzesniowsky, o"f the University of Warsaw, to Dr. Giinther, by whom they were intrusted to me for determina-tion and description. The collection contained also a few Old-World species from various localities, which are described separately at the end of the paper. I have also added descriptions of species belong-ing to the same genera in the collection of the British Museurn, which have hitherto been unrecorded, or known only from names' without descriptions applied to them by A. White, in the • List of Crustacea of the British Museum,' 1847. In all, 37 species are noticed, of which 27 are from the New, and 10 from the Old World, viz. Brachyura 5 species, Anomura 7 Macrura 5, Isopoda 20. Of these 22 appear to have been hitherto undescribed, viz. Brachyura 1 species, Anomura 6, Macrura 2, Iso])oda 13. I have carefully noted such variations as I have observed between mdividuals of the same species— the nomenclature having often been needlessly encumbered by the description of nominal species, based only upon sexual or other differences, which the examination of a good series of specimens would have shown to be insufficient. I have also endeavoured to compare the species described with their allies, although in the case of the terrestrial and fluviatile Decapoda and ter-restrial Isopoda this has generally been attempted only as far as theii-congeners inhabiting the same continent are concerned. Many, indeed , of the European Isopoda are only known to me by descriptions so' short and superficial as to render their determination a matter of great difficulty, and their comparison with the New-World species described in the following paper impossible. List of the Species described. The names of the species in the collection from Warsaw are in Roman type, those described from specimens in the collection of the British Museum are in italics. New-world Species. DECAPODA. Beachyura. Acanthonyx petiverii, M.-Edw. ? Peru. Hepatus chilensis, M.-Edw. Peru Neptunus anceps, Saussure. Marti-tubermilattis, Saussure (adulO "ique. W. Indies, Cayenne. ' Proc. Zool. Soc— 1877, No. XLIIL 43
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