One of the species similar in structure to Hall's type, but budding out into turbinate branches, was discovered by Mr. E. T. Chambers, of Montreal, in the Ordovician limestone of Lake St. John, and has been named _C. boreale_. It differs in structure from Hall's species in having the tubes less tortuous and more nearly parallel to the laminæ. In its outline it reminds one of the problematical Eozoon from the Hastings group at Tudor, Ontario, referred to in the text. Should time permit, I hope to have all the specimens in our collections illustrating this interesting and primitive type examined and described. In the meantime I may merely remark that a near modern analogue would seem to be the gigantic arenaceous Foraminifer _Neusina Agassizi_, Goës, dredged by Alexander Agassiz in the Pacific, and described in the Bulletin of the Museum of Comparative Zoology (Vol. xxiii., No. 5, 1892). The modern form, it is true, is flat and foliaceous; but some of the old species approach to this shape, and if we suppose the little cells of Neusina to represent the tubes of Cryptozoon, and the carbonaceous matter of the latter to be the remains of the chitinous stroma seen in some specimens, the general resemblance will be very close. The whole subject of these peculiar Stromatoporoid forms extending from the Upper Cambrian to the Laurentian, deserves a full and careful investigation, for which I am endeavouring to collect material. * * * * * E. Receptaculites and Archæocyathus. In "The Dawn of Life" (1875), reference was made to the singular and complicated organisms of the Upper Cambrian and Ordovician systems known as Receptaculites, which at that time was generally regarded as foraminiferal, and is still placed by Zittel, in his great work on Palæontology, among forms doubtfully referable to that group. It has also been referred to Sponges, though on very uncertain grounds. It has not, however, so far as I am informed, been traced any farther back than the Upper Cambrian (Calciferous), and no structural links are known to connect it with either Eozoon or Archæozoon. For this reason it was omitted in the text; but I think it well to mention it here, and to direct attention to it as possibly one of the complex Protozoa which may be traced far back toward the beginnings of life.[57] [Footnote 57: Billings, "Palæozoic Times."] Another primitive and generalized genus mentioned in the text is _Archæocyathus_ of Billings, whose headquarters seem to be in the Lower Cambrian, and which may probably be traced farther back. Mr. Billings described the genus in his "Report on Canadian Fossils" (1861-64), taking _A. profundus_, from the Lower Cambrian of L'Anse à Loup, on the Labrador coast, in the first instance, as the type.