If we exclude the alleged _Palæorbis_ referred to below, all the Palæozoic Pulmonifera hitherto found are American. Since, however, in the Carboniferous age, Batrachians, Arachnidans, Insects and Millipedes occur on both continents, it is not unlikely that ere long European species of land snails will be announced The species hitherto found in Eastern America are in every way strangely isolated. In the plant beds of St. John, about 9,000 feet in thickness, and in the coal formation of the South Joggins, more than 7,000 feet in thickness, no other Gasteropods occur, nor, I believe, do any occur in the beds holding land snails in Illinois. Nor, as already stated, are any of the aquatic Pulmonifera known in the Palæozoic. Thus, in so far as at present known, these Palæozoic snails are separated not only from any predecessors, if there were any, or successors, but from any contemporary animals allied to them. It is probable that the land snails of the Erian and Carboniferous were neither numerous nor important members of the faunas of those periods. Had other species existed in any considerable numbers, there is no reason why they should not have been found in the erect trees, or in those shales which contain land plants. More especially would the discovery of any larger species, had they existed, been likely to have occurred. Further, what we know of the vegetation of the Palæozoic period would lead us to infer that it did not abound in those succulent and nutritious leaves and fruits which are most congenial to land snails. It is to be observed, however, that we know little as yet of the upland life of the Erian or Carboniferous. The animal life of the drier parts of the low country is indeed as yet very little known; and but for the revelations in this respect of the erect trees in one bed in the coal formation of Nova Scotia, our knowledge of the land snails and Millipedes, and also of an eminently terrestrial group of reptiles, the _Microsauria_, would have been much more imperfect than it is. We may hope for still further revelations of this kind, and in the meantime it would be premature to speculate as to the affinities of our little group of land snails with animals either their contemporaries or belonging to earlier or later formations, except to note the fact of the little change of form or structure in this type of life in that vast interval of time which separates the Erian period from the present day.