In the absence of evidence to the contrary, it is reasonable to suppose that the mass forwarded by General Carleton is the one spoken of by Mr. Bartlett as “another larger mass,” and of which no drawing was made; while, on the other hand, a piece was taken for analysis. This piece is almost certainly the one analyzed by Dr. Smith, and hence the close agreement in the two analyses—this chemist, however, not having apparently made so complete a separation of the nickel as Prof. Brush has done. Still it is possible, of course, that different portions of the mass may differ slightly in composition. Dr. Blake read the following paper: Infusoria from the Moving Sands in the Neighborhood of San Francisco. BY JAMES BLAKE, M.D., F.R.C.S. The infusoria to which I would call the attention of the Society, were collected from the sands in the neighborhood of Point Lobos. These sands form a moving surface, which in dry weather is drifted by the prevailing winds from the shore of the ocean landwards, and are entirely devoid of any signs of vegetation for some distance from the shore. On walking over these sands when a strong north-west wind was blowing, a wind that does not bring up any fresh sand from the ocean beach at that part of the sand field, I noticed a number of small sized bodies projecting above the surface of the sand as it was being carried onwards by the wind. A closer examination showed that these bodies were formed of particles of sand, agglutinated together by some substance which rendered them almost black, and where dried possessing considerable tenacity. Some of these bodies projected as much as an inch and a half above the surface of the sand, with which however they all remained connected, forming generally small ridges. On examining a portion of this agglutinated sand under the microscope, the water with which I had moistened it was found to be full of infusoria, which commenced moving about as soon as the sand was moistened, although it had been quite dry for some days before being examined. These infusoria probably belong to the genus Monas, but they are so extremely minute that it was impossible to resolve them; they were, in fact, the smallest living infusoria I had ever examined. With a quarter-inch object glass of Powell and Lelands, they appeared as small globular moving bodies, although occasionally a movement would present one of them with apparently a narrow edge. Nothing much more definite could be made out with the microscope of my friend, Dr. Trask, when using an eighth object glass of Smith and Beck, as they could not be resolved into any form sufficiently definite to classify them. They appeared mostly as globular bodies moving about slowly, and presenting sometimes a longer axis, one end being larger than the other,