PERHAPS some of the readers of NATURE may be able to throw some light on the present geographical range of the Black Rat (Mus rattus, L.). In the early part of 1877 some individuals of this species came on board the steamship Lady Frances either at Bombay or at Rangoon, but, as the captain believes, at the latter port. The animals multiplied on board the vessel, and in August last I had the pleasure of receiving from the ship a living specimen, which was at once forwarded to the Zoological Gardens in Regent's Park, where, I believe, it may still be seen. In a “Catalogue of the Mammals of the Sahara,” by my friend, Canon Tristram, F.R.S. (vide “The Great Sahara,” p. 385), the author states that the “Far el Kla”, as the black rat is called by the Arabs, “still maintains its position” in the Algerian Sahara. And I was yesterday presented by Mr. F. Donald Thompson, of Seaton-Carew, with a skin of Mus rattus from New Zealand. This example, like those from Burmah, was brought over by a vessel (the Trevdyan) which loaded grain at Lyttelton, in the province of Canterbury, New Zealand, where the rats embarked. In August, 1878, Dr. Sclater, F.R.S., was good enough to inform me that “Mus rattus has rather an extensive range over Europe and Western Asia”, and added, “I fear it would not be possible to state it very exactly”. But it is evident that the range of the species is much wider, as it is known to occur in North Africa, British India, and New Zealand; and it is also said, by Prof. Bell and Mr. Macgillivray, to have been carried to America and the South Sea Islands by ships. I should be glad to have further evidence as to its occurrence in Burmah, and it would be also desirable to know if it is found in the Malay Archipelago, China, Japan, or Australia. Dr. Peters, of the Zoological Museum at Berlin, assured me, in June last, that the species was extremely rare, if not actually extinct, in Germany, and showed me the only specimen in the fine collection under his care—an old and faded skin from Hanover. The animal lingers in one old building at Stockton-on-Tees, and there is clearly a possibility of its being reintroduced in many seaport towns through the agency of ships.