The middle of the eighteenth century is approximately the period in which the collection and classification of exotic plants and animals became one of the chief objects of exploratory voyages. This was also one of the aims of the expedition under the command of Marion and Commerson, a botanist who had accompanied De Bougainville, was to have accompanied Marion also. But he was unable to go, so that no botanist and also no zoologist made the voyage. Crozet, however, who was second in command of the _Mascarin_, has left not a few observations relating to the birds which he saw at sea during the voyage, or in the countries which he visited. They are embodied in his book _Nouveau Voyage a la Mer du Sud_. The native of Tahiti fell sick shortly after the commencement of the voyage, and was put ashore in Madagascar, where he died. One of the objects of the voyage thus ceased to exist. The first undiscovered land which was sighted after leaving Madagascar was named Terre d'Esperance, and subsequently, by Cook, Prince Edward Island. Near it a collision with the _Mascarin_ caused the partial disablement of the _Marquis de Castries_; the search for a southern continent was therefore abandoned, and it was resolved to visit the countries which had been discovered by Tasman in the seventeenth century. Crozet's first observation relating to sea-birds was made on the 8th of January, 1772, about twelve days after leaving the Cape of Good Hope. Terns were then in view, and thereafter, until the 13th of that month, Terns and Gulls were frequently seen. Shortly after the latter date Du Clesmeur, who was in command of the _Marquis de Castries_, sighted another island which was named Ile de la Prise de Possession, and which has been renamed Marion Island. Crozet landed upon it, and relates that the sea-birds which were nesting upon it continued to sit on their eggs or to feed their young regardless of his presence. There were amongst the birds penguins, Cape petrels ('damiers'), and cormorants. Crozet also mentions divers--'plongeons.' It is doubtful to what birds he alludes under this name--a name which is usually applied to the Colymbidae, a family which has no representative in the seas of the southern hemisphere.