1. Sir Everard Home has given an account of the organs of respiration in a class of animals intermediate between the pisces and vermes, and in two genera of the last mentioned class. In the lamprey the organs of respiration have seven external openings on each side of the animal. These lead to the same number of oval bags, the inner membrane of which is constructed like the gills of fishes. These organs are inclosed in a cartilaginous thorax, and a pericardium acting the part of a diaphragm, by the actions of which the water is admitted and expelled.

In an animal brought from the South Sea by Sir Joseph Banks, intermediate between the lamprey and myxine, but constituting a particular genus, the external openings and bags are the same as in the lamprey, but there is no thorax. The water is drawn in and expelled by the elasticity of the bags.

In the myxine there are only two external openings and six lateral bags on each side, to which there are six tubes from each of the openings.

In the aphrodita aculeata there are 32 openings on each side. These all open into a large bag immediately under the skin andmuscles of the back, which is only separated from the cavity of the abdomen by a strong cartilaginous membrane; but there are two rows of spherical cells projecting into the cavity with very thin membranous coats. A cœcum from the intestine is lodged in each cell. These appear to be the principal respiratory organs.

In the leech there are 16 orifices on each side of the belly, which lead to an equal number of spherical cells, placed between the abdominal muscles and the stomach.

2. Sir Everard Home has ascertained that both the lamprey and myxine are hermaphrodites.

3. Dr. Wilson Philip has published two curious papers, in which he relates a great number of experiments made in order to determine the principle on which the action of the heart depends. He has shown that both the brain and spinal marrow may be removed without affecting the motion of the heart; but that if they be suddenly destroyed, as by crushing them, the motion of the heart is affected. He explains these apparently contradictory experiments thus: in man there are three systems-the sensorial, the nervous, and the muscular, all independent of each other, but capable of affecting each other. In his second paper he shows that a stimulus applied to the brain in general accelerates the motion of the heart; but that the action of the voluntary muscles is only excited by stimulating the part of the brain from which their nerves proceed. Ganglia, in his opinion, convey to the nerves which proceed from them the united energy of all the parts of the brain from which nerves going to them proceed, and they have no other use.

4. Mr. Clift has ascertained, by a set of experiments on carp, that the brain of that fish may be removed, and the spinal marrow destroyed, without stopping the motion of the heart; but the action of the voluntary muscles was immediately destroyed. He found

that when the heart of a carp was laid open, it ceased to beat much sooner if the fish was allowed to swim in water than if it was kept quiet in the air.

5. From the discovery of Mr. Rose that urine in hepatitis contains no urea, I think it may be inferred that one use of the liver, if not the only one, is to separate urea from the blood; so that it would seem to be the principal organ concerned in the formation of urine.

XI. ZOOLOGY.*

The division of animals into four types has been carefully examined and discussed by several learned zoologists, who are.. much divided in their opinion as to the correctness of this distribution, which was proposed a few years since by M. G. Cuvier.

That the vertebrous, molluscous, and annulose animals form three great and natural groups, is certain; and it is probable that the radiated animals form another. The questions to be decided are: Where are we to place the lamprey and myxine, animals having no vertebræ or jaws; but agreeing with the vertebrosa in most other points? And where the cirrhipedes, whose structure is partly that of the mollusca and partly of the annulosa? Dr. Blainville conceives that the cirrhipedes offer no obstacle to this distribution, and that they form what he calls a subtype, intermediate between the mollusca and annulosa; and Dr. Leach entertains the same opinion. Many of the French zoologists still maintain Lamark's division of animals into those with and into those without vertebræ.

Le Sueur, Desmarets, and Savigny have discovered that the animals of the genus pyrosama, of some alcyonia,† and flustræ, are genuine mollusca, and not zoophytes. M. Savigny names these animals ascidées composées; and he has written a monograph on them, which was read to the Institute of France.

Dr Leach has published a general classification of the animals named by Linné insecta, which he considers as forming one group, and the vermes another of the type annulosa. In the dissertation which is published in the last number of the Linnæan Transactions, these animals are considered as forming four classes: viz. 1. Crustacea: 2. Myriapoda: 3. Arachnides: 4. Insecta. The myriapoda were considered by Latreille as belonging to the arachnides but they were published as a distinct class by Dr. Leach, in the seventh volume of the Edinburgh Encyclopædia, three years ago.

M. Savigny has discovered that mandibles and maxillæ exist in the lepidopterous and hemipterous insects, although in a modified form. And Sir J. Banks observed, that the palpi of spiders were in fact legs; this was also noticed by Dr. Blainville about the same time, and he has proposed a division founded on the number of the legs of this group.

*For the account of the improvements in this branch of science the editor is indebted to a friend.

The animals of alcyonium digitatum are true zoophytes.

In the crustacea malacostraca are always to be observed one pair of mandibles, two pair of maxillæ, and sixteen legs, the three foremost of which generally assume the form of maxillæ and bear palpi at their extremities. In Insecta are to be observed one pair of mandibles, one pair of maxillæ distinct; the exterior pair coalescing so as to form the under lip, which, like the interior maxillæ, bears palpi.

Such are the important discoveries of the last year, which has done more for the advancement of zoological science than the preceding 13 years.

ARTICLE II.

Note by Professor P. Prevost respecting Dew, in consequence of the Answer of Dr. Wells inserted in No XXXVI. of the Annals of Philosophy.

AFTER reading Dr. Wells's answer, and before perusing the letter to which he refers (Annals of Philosophy, vol. v. p. 251), I hasten to thank him for the information which he has given me.

1. I observe, that in explaining the principal phenomenon to which Mr. Benedict Prevost has reduced the results of his experiments, I have said positively that I did not pretend to have explained all the details, and that I thought it sufficient to have clearly explained one of the causes of that class of facts (Calorique Rayonn. § 207).

2. Dr. Wells thinks that dew can never be deposited upon the side of a glass. which is exposed to air colder than itself.

This does not invalidate my explanation, but is inconsistent with the assertion of Mr. Benedict Prevost, who affirms that in order that dew be deposited on the outside of glasses, it is not necessary that the temperature on the outside should be greater than that on the inside (cited Calor. Rayonn. § 193, n. 24, p. 241). In the dissertation itself, from which I have quoted a mere extract, that philosopher says expressly" that exterior humidity is very often deposited though the external air be colder than the internal. Mr. Benedict Prevost supposes this fact in his first generalization (cited Calorique Rayonn. § 194, n. 1). I intend to request him to give us his proofs.

All this discussion must tend to the advantage of the science. I am delighted, therefore, that Dr. Wells has produced it. This is an additional obligation to all those for which science is indebted to him.

Geneva, 1815.

ARTICLE III.

A Journey into the Interior of New South Wales, across the Blue Mountains, performed by his Excellency Colonel Macquarrie, Governor of the Settlement. From the Official Account, dated Sydney, June 10, 1815. With a Plan.

THE Governor desires to communicate, for the information of the public, the result of his late tour over the Western or Blue Mountains, undertaken for the purpose of being enabled personally to appreciate the importance of the tract of country lying westward of them; which had been explored in the latter end of the year 1813, and beginning of 1814, by Mr. George William Evans, Deputy Surveyor of Lands.

To those who know how very limited a tract of country has been hitherto occupied by the colonists of New South Wales, extending along the eastern coast to the north and south of Port Jackson only 80 miles, and westward about 40 miles, to the foot of that chain of mountains in the interior which forms its western boundary, it must be a subject of astonishment and regret that amongst so large a population no one appeared within the first 25 years of the establishment of this settlement possessed of sufficient energy of mind. to induce him fully to explore a passage over these mountains; but when it is considered that for the greater part of that time even this circumscribed portion of country afforded sufficient produce for the wants of the people, whilst on the other hand the whole surface of the country beyond those limits was a thick and in many places nearly an impenetrable forest, the surprise at the want of effort to surmount such difficulties must abate very considerably.

The records of the colony only afford two instances of any bold attempt having been made to discover the country to the westward of the Blue Mountains. The first was by Mr. Bass, and the other by Mr. Caley, and both ended in disappointment; a circumstance which will not be much wondered at by those who have lately crossed those mountains.

To Gregory Blaxland and William Wentworth, Esqrs. and Lieut. Lawson, of the Royal Veteran Company, the merit is due of having, with extraordinary patience and much fatigue, effected the first passage over the most rugged and difficult part of the Blue Mountains.

The Governor being strongly impressed with the importance of the object, had, early after his arrival in this colony, formed the resolution of encouraging the attempt to find a passage to the western country, and willingly availed himself of the facilities which the discoveries of these three Gentlemen afforded him. Accordingly, on the 20th of November, 1813, he entrusted the accomplishment of this object to Mr. George William Evans, Deputy Surveyor of Lands, the result of whose journey was laid before the