Though I have confined myself in this notice to plants, or supposed plants, of the Lower Palæozoic, it may be well to mention the remarkable Cauda-Galli fucoids, referred by Hall to the genus _Spirophyton_, and which are characteristic of the oldest Erian beds. The specimens which I have seen from New York, from Gaspé, and from Brazil, leave no doubt in my mind that these were really marine plants, and that the form of a spiral frond, assigned to them by Hall, is perfectly correct. They must have been very abundant and very graceful plants of the early Erian, immediately after the close of the Silurian period. We come now to notice certain organisms referred to Algæ, and which are either of animal origin, or are of higher grade than the sea-weeds. We have already discussed the questions relating to _Prototaxites_. _Drepanophycus_, of Goeppert,[AB] I suspect, is only a badly preserved branch or stem of the Erian land-plant known as Arthrostigma. In like manner, _Haliserites Dechenianus_,[AC] of Goeppert, is evidently the land-plant known as _Psilophyton_. _Sphærococcites dentatus_ and _S. serra_--the _Fucoides dentatus_ and _serra_ of Brongniart, from Quebec--are graptolites of two species quite common there.[AD] _Dictyophyton_ and _Uphantenia_, as described by Hall and the author, are now known to be sponges. They have become _Dictyospongiæ_. The curious and very ancient; fossils referred by Forbes to the genus _Oldhamia_ are perhaps still subject to doubt, but are usually regarded as Zoöphytes, though it is quite possible they may be plants. Though I have not seen the specimens, I have no doubt whatever that the plants, or the greater part of them, from the Silurian of Bohemia, described by Stur as Algæ and Characeæ,[AE] are really land-plants, some of them of the genus _Psilophyton_. I may say in this connection that specimens of flattened _Psilophyton_ and _Arthrostigma_, in the Upper Silurian and Erian of Gaspé, would probably have been referred to Algæ, but for the fact that in some of them the axis of barred vessels is preserved. [AB] "Fossile Flora," 1852, p. 92, Table xli. [AC] _Ibid._, p. 88, Table ii. [AD] Brongniart, "Vegeteaux Fossiles," Plate vi., Figs. 7 to 12. [AE] "Proceedings of the Vienna Academy," 1881. _Hostinella_, of this author, is almost certainly _Psilophyton_, and his _Barrandiana_ seems to include _Arthrostigma_, and perhaps leafy branches of _Berwynia_. These curious plants should be re-examined.