III. Preliminary remarks on the development of some pelagic decapods

Since we left Australia I have investigated the metamorphoses of some Crustacea which have been constantly caught by us on the surface of the tropical and subtropical parts of the Pacific. Though these investigations will be continued, I have now arrived at certain results which I think will not be uninteresting to zoologists. The genera to which these remarks refer areAmphion, Sergestes , andLeucifer .Amphion Reynaudi has been on our lists as an animal “incertæ sedis ” (Milne-Edwards) for nearly forty years, until Dohrn proved that a fullgrown specimen of it, which he dissected, was in possession of branchiæ and of an ovary, therefore no doubt a mature form. He also described one of its young stages, which has the number of appendages of aZoëa , but in which caudal appendages are already developed.