Dr. Packard's observations on the structure of the Phyllopoda, and his comparative anatomical studies of allied living and extinct genera, supply the palæontologist with sound reasoning for referring the Phyllocarida to the Nebaliad type as a centre for a great group of obscure fossil forms, and as a starting-point for the Decapoda. His views have been referred to in some detail in the Geol. Mag. for August last, pages 349–352.

Geology has long been the handmaid of Engineering. Instances are numerous in which the practical bearing of facts discovered by the devotee of the one have been recognized and utilized by the other. On the other hand, engineering enterprise has often put geologists in possession of facts of the greatest value as bases for fresh inductions. The subject now brought forward may perhaps sooner, or in a remote future, furnish another instance in which knowledge gained by the geologist may become available for a great economic purpose.

It was indicated even by Murchison that the Graptolites constitute admirable characteristic fossils of the Silurian formation. Subsequent investigation has established that the group Graptolithidæ is essentially confined to the oldest fossiliferous formation. A single genus, the genus Dictyograptus, Hopk. (Dictyonema, Hall), occupies a remarkably exceptional position as regards its distribution in time. Formerly, indeed, this genus was separated from the proper or true Graptolites (Rhabdophora, Allman), and referred with some other genera (Dendrograptus, Hall, Ptilograptus, Hopk., Callogroptus, Hall) to the Campanularidæ but recently W. C. Brögger has very clearly shown that the genus in question differs very little from the true Graptolites, inasmuch as the most important parts of the latter, such as the sicula, and the hydrothecæ, have been detected in it. By this the Graptolithic nature of the genus in question is rendered very probable. Members of the genus Dictyograptus, Hopk., appear among the very oldest of known Graptolites; the genus maintains itself throughout the whole of the Silurian formation, while by its side new genera make their appearance, culminate and disappear. Even after the other Graptolites had long since disappeared from the ancient sea-fauna, this genus still lived on, for we find it occurring in the Devonian.

Among the vast additions which, during the past five years, have been made to the palæontological collections in the British Museum (Natural History), none probably possess greater interest to the naturalist and comparative anatomist than the remains of the very remarkable group of aquatic phytophagous mammals known as the Sirenia, of which the “Manatee” and the “Dugong” are the living representatives.

As facts relative to the earliest forms of Molluscs are of interest to the naturalist as well as the geologist, I offer this note on the genus Stenotheca, derived from a study of the remains of several species occurring in the Cambrian rocks of Canada. The formation in which they are found is the St.-John Group, a formation occurring in the Southern part of the Province of New Brunswick; and the geological horizons are those of the Solva and Menevian Groups of Wales, equivalent to the Paradoxides-Tesseni beds, and overlying measures of Étage 1, of the Norwegian geologists. The fossils are, therefore, of great antiquity, having preceded any known Lamellibranchs; and, except the Metoptoma Barrandei of Linnarsson, I know of no Gasteropods of equal antiquity.