The author, after quoting from the works of writers on Ichthyology and Comparative Anatomy their descriptions of the vertebral columns of cartilaginous fishes, proceeded to point out the existence of an osseous structure in the vertebræ of the Plagiastomi, or Rays and Sharks. In thse animals the essential portion of each vertebra consists of a double cup or saucer-shaped osseous piece, resembling in form and structure the double cup-shaped vertebræ of osseous fishes, being, like them, composed of concentric rings of osseous matter.

The Acephalocyst or Hydatid is composed of a vesicle containing fluid. It propagates by means of internal gemmules, which are developed between the layers of the membrane composing the vesicle, and, after a certain time, are thrown off internally.

The author, after pointing out these distinguishing characters of the Hydatid, referred to the confusion which had arisen, from want of proper observations on this point, and which, with other causes, had been the reason why the animal nature of these creatures had been denied by some writers of great authority.

The authors commenced with an account of the trials they made with the Cyanide of lead; which, according to Dr Brown's most recent announcement, is resolved by his process into gaseous nitrogen and silicon. In the first place, however, they could not succeed in obtaining a pure cyanide of that metal. For whether they decomposed the cyanide of potassium, or the hydrocyanate of ammonia containing an excess of hydrocyanic acid, by neutral acetate of lead, by this salt acidulated with acetic acid, or by tribasic acetate, they constantly obtained a compound containing a large quantity of a hydrated basic acetate of lead; and they were not more successful when they substituted other salts of lead for the acetate as a precipitant, such as the nitrate, basic nitrate, nitrite, chloride, or iodide.

In the first part of the present memoir, it was shewn that Cæsar divided Gaul into three parts, of which one was inhabited by the Belgæ, another by those who, in their own language, were called Celtæ, but who, by the Romans, were named Gauls, and a third by the Aquitani. These three nations, according to the Roman historian, differed from each other in language, custom, and laws; but it was remarked by the author, that they also differed from each other in physical characters,—the Belgæ possessing what is named a Cymric type, the Gauls proper a Gaulish type, and the Aquitani an Iberian type. All these three races were to be distinguished from the zanthous, light-haired, Germanic tribes of the West of Europe, not only by the dark colour of the hair and eyes, but by other particulars, as the form of the head, &c.

The author, in the first part of his paper, described the nature of the formations, and in the last part offered his views in explanation of the appearances.

In describing the formations, he enumerated, first, those of aqueous, and last those of ligneous origin.

I. The former consist of the greywacke, the old red sandstone, and the coal-measure formations.

The oil known as Indian Grass Oil, has been referred by Dr Royle to the Andropogon Calamus-aromaticus, a plant which he conceives to be identical with the Καλαμος αζωματιχος of the Greeks. It has been used in medicine as a stimulant embrocation in rheumatism, &c.

The oil, which was green, became yellow when heated. It acquired a steady boiling point at 440°, between which temperature and 442°, a transparent colourless oil distil over.