The Solitaire of Rodriguez was first satisfactorily shown to be distinct from the Dodo of Mauritius ( Didus ineptus ) by Strickland in 1844, from a renewed examination of the evidence respecting it, consisting of the account given by Leguat in 1708, and of the remains sent to France and Great Britain. Strickland, in 1848, further proved it to be generically distinct from the Dodo. The remains existing in Europe in 1852 were eighteen bones, of which five were at Paris, six at Glasgow, five in possession of the Zoological Society (since transferred to the British Museum), and two in that of Strickland, who, at the date last mentioned, described them as belonging to two species, the second of which he named Pezophaps minor , from the great difference observable in the size of the specimens. In 1864 one of the authors visited Rodriguez, and there found in a cave two more bones, while a third was picked up by a gentleman with him. All these bones have been described, and most of them figured, in the publications of the Zoological Society, and in the large work of Strickland and Dr. Melville. Encouraged by his former success, that one of the authors of the present paper who had before been to Rodriguez urged Mr. George Jenner, the magistrate of the island, to make a more thorough search in its caves; and in 1865 this gentleman sent no less than eighty-one specimens to Mauritius. These were forthwith transmitted to London, and exhibited at a meeting of the Zoological Society in that year, when it appeared that the notion previously entertained of there having been two species of Pezophaps was erroneous, and that probably the difference in size of the specimens was sexual.