As far as I am aware, Quekett has been the first to point out that vegetable parasites, viz.
Confervæ
, occur frequently in the skeleton of Corals (Lectures on Histology, vol. ii. p. 153. fig. 78. and p. 276); but although he mentions in the same place that the
tubuli
described by Carpenter in the shells of Bivalves have also a great resemblance with
Confervæ
, he did not venture any further step, and he adheres to the view of Carpenter, who regards them as a typical structure. Some years later, Rose ( “On Parasitic Borings in Fossil Fish-Scales,” Transactions of the Microscopical Society of London, vol. x. p. 7, 1855) discovered a peculiar tubular structure in fossil fish-scales, which he regarded as being occasioned by parasites, and possibly by Infusoria, but he was not able to give any good proof of this hypothesis. The same must be said of E. Claparède (Müll. Archiv, 1857, p. 119), who found similar canals in the test of
Neritina fluviatilis
, and showed that they do not really belong to the shell, without being happier in determining the nature of the parasite, only suggesting that it might possibly be a sponge. Such was the state of things, when Prof. Wedl of Vienna and I, independently of each other, took up the question. The observations of Wedl, which concern only the parasites of the shells of Bivalves and Gasteropods, were communicated to the Vienna Academy on the 14th of October, 1858, and are therefore previous to my own, which were presented to our Würzburg Society on the 14th of May, 1859; but I received Wedl’s memoir only on the 16th of May, and may therefore say that my observations, which are also extended over many more groups of animals, were quite independent of those of the Austrian microscopist. This being the case, it may be regarded as a good proof of the correctness of our observations and the truth of our conclusions, that we agree in the principal facts, there being only this discrepancy between us, that Wedl calls the parasites
Confervæ
, whilst I regard them as
Unicellular Fungi
. The botanists will decide this question better than we; only I beg leave to say, that all the numerous parasites observed by myself were
unicellular
, and that the
sporangia
were quite of the same kind as those of unicellular fungi. I may further add, that the frequent anastomoses of the parasitic tubes remind one of the anastomoses observed in the mycelium of some unicellular fungi, whereas such connexions have not yet, so far as I know, been observed amongst the
Confervæ
.
PRELIMINARY REPORT ON THE LACUSTRINE STRATA OF THE SANFRANCISCANA BASIN IN NORTHERN MINAS GERAIS, BRAZIL
