spawned salmon weighing 12lb. was marked on the 4th of March, and was recaptured on its return from the sea on the 10th of July, weighing 18lb. Mr. Young is of opinion that salmon rather diminish than increase in size during their sojourn in rivers; and he illustrates this and other points of his subjects by numerous experiments and observations. Proceedings of the Royal Society of Scotland.

SHELL-FISH AND POLYPI OF THE RED SEA.

A FRENCH naturalist at Cairo offers to go to the Red Sea and collect specimens of the Shell-fish and Polypi of every description, when he shall have procured twenty subscribers at £1 per month for a year. For this sum he proposes to give each subscriber a certain number of specimens of each shell polypus, which is to be sent monthly to Cairo, to a committee, formed of the most respectable resident subscribers. I have seen a collection already made by him from the north end of the Red Sea, in which are most rare and curious shells. I believe the man to be honest, and that his subscribers will possess, at the end of the year, for the sum of £12, a valuable series of shells and polypi from the whole western coast and islands of that sea, from Suez to Abyssinia.-Letter in the Athenæum.

ORGAN OF HEARING IN CRUSTACEA.

A

DR. FARRE finds that in the Lobster (Astacus marinus), the organ of hearing consists of a transparent and delicate vestibular sac, which is contained in the base, or first joint of the small antennæ; its situation being indicated externally by a slight dilatation of the joint at this part, and also by the presence of a membrane covering an oval aperture, which is the fenestra ovalis. The inner surface of the sac gives origin to a number of hollow processes, which are covered with minute hairs, and filled with granular matter, apparently nervous. delicate plexus of nerves, formed by the acoustic nerve, which is a separate branch supplied from the supra-oesophageal ganglion, is distributed over the base of these processes and around the sac. Within the sac there are always found a number of particles of siliceous sand, which are admitted, together with a portion of the surrounding water, through a valvular orifice at the mouth of the sac, being there placed apparently for the express purpose of regulating the size of the grains. Dr. Farre considers these siliceous particles as performing the office of otolites, in the same way as the stones taken into the stomachs of granivorous birds supply the office of gastric teeth. The Doctor describes several modifications of this structure exhibited in the organs of hearing of the Astacus fluviatilis, Pagurus streblonyx, and Palinurus quadricornis, and an explanation is attempted of the uses of the several parts, and their subserviency to the purposes of that

sense.

The Doctor describes another organ situated at the base of the large antennæ, which it appears has been confounded with the former by some anatomists, but which the Doctor conjectures may possibly constitute an organ of smell.-Proceedings of the Royal Society.

ANIMALS OF THE EGEAN SEAS.

PROF. FORBES has read to the British Association, a lecture "On the Dredging of the Ægean Seas, to determine their Marine Animals," which had never before been satisfactorily done. With respect to the cause affecting their distribution, a few of the results arrived at were, that the species found in the lesser depths are those common to all countries, while the deep yield the exclusively local; and the species diminish in number as we descend. The regions of depth are proportioned to the latitude, so that as we descend, the fauna assumes a more northern character, more colourless and dusky. Now, combining all these facts with the well-known one, that the Ægean is filling up with sedimentary deposits, were the process complete, we should find a varied fauna at the top, becoming more and more simple in its character as we descend in each layer, until we reach the zero of animal life, where no traces of living fauna could be found. In some localities, land and sea shells will be found mingled. The Professor thought the application of this to geology evident.

IRISH LIMAXES.

A PAPER, by the Rev. J. Clarke, "On the Irish Species of the Genus Limax," has been read to the British Association. Two species were described in detail, which had not been included, by previous writers, in the British catalogue—the Limax aboreus of Bouchard, and the L. Gagates of Draparnaud and Ferussac. The L. aboreus is not uncommon in the wooded districts of Ireland, especially on the ash and the beech; concealing itself during the day-time under the moss and the trunk. Limax Gagates (Draparaund), the Irish specimens of this limax, agree with Ferussac's variety B. The only British species with which it can be compared, as to form, is L. Sowerbii. In some districts of Ireland the species is not uncommon; frequenting gardens and thick herbage. In the course of the paper, all the British Limaxes were mentioned as occurring in Ireland, with the exception of Limax brunneus (Draparaund), which had not as yet come under the notice of the author.

Prof. Forbes considered this as one of the most valuable papers that had been written on the genus Limax, which had been little attended to, though forming an important link in the scale of creation. Mr. Thompson observed, that this paper was interesting, as recording two forms of Limax in Ireland, which were not only new to Ireland, but did not at present exist in the British Fauna.

ARANEIDE.

A REPORT has been read from Mr. Blackwall to the British Association, "On the Functions of the Palpi of the Araneidæ," which had been called for at the last meeting of the Society. After stating all the opinions hitherto formed, as to the functions of the palpi of the Araneidae, the author detailed a series of experiments on the subject, and the conclusions derived from them. Prof. Owen acknowledged the pleasure with which he had listened to this paper, and gave a complete

view of the difficulties attending the assignment of the true function to the palpi of spiders. In alluding to a portion of Mr. Blackwall's paper, he gave an account of the structure and functions of the ovarial sac of aphides, accounting for the well-known fact of the anomalous reproduction to which they were subject.

BEES.

IN a note to the French Academy, M. Muston mentions a fact, which he did not observe directly, but which had been attested to him by different inhabitants of the country, that a Bee, which goes out of its hive, from the commencement to the end of its excursion only rests on flowers belonging to the same species, or to species closely allied. -Illustrated Polytechnic Review, No. 13.

ZOOPHYTES OF IRELAND.

DR. ALLMAN has read to the British Association, a "Synopsis of the Genera and Species of Zoophytes inhabiting the fresh waters of Ireland." The fresh-water Zoophytes of Great Britain have hitherto been all included under the following four genera :-Hydra, Cristatella, Alcyonella, and Plumatella. Of these, Hydra is made to include four British species,-Cristatella one, Alcyonella one, and Plumatella has been described as containing three species. Of the above nine species, the author was of opinion that two must be erased, viz. the Hydra verucosa of Templeton, which appears identical with H. fusca, and the Plumalella gelatinosa of Flemming, which is evidently the same with Blumenbach's Tubularia sultana. To the seven species which remain, Dr. Allman was enabled to add five, of which four do not appear to have been before noticed, and the other is only found described in the Fauna of the Continent. The Zoophytes at present included under Plumatella were distributed in the synopsis between two genera-those with crescentic disks being retained under Plumatella; while those whose disks are circular were removed to Fredericella, a genus established by M. Gervais for this form of ascidian zoophyte. An important addition now made to the British zoophytes is Paludicella, discovered by W. Thompson, Esq., at Lough Erne, in the autumn of 1837, and since obtained abundantly by Dr. Allman in the Grand Canal near Dublin. In October, 1842, a hydroid zoophyte of much interest was discovered by Dr. Allman in the Grand Canal, Dublin; it is referable to no known genus, and occupies a position between Coryne and Hermia. For the reception of this zoophyte, therefore, he has been obliged to form a new genus, to which he has given the name Cordylophora. The synopsis, therefore, embraced several new species and two genera, now for the first time added to the British Fauna.

Prof. Forbes remarked on the value of this paper. In Fredericella, we had the analogue of the marine genus Coryne, as we had in Hydra, that of Sertularia. This paper pointed out the impossibility of the existence of such a genus as Hassell's Echinochorium.

NEWLY-DISCOVERED PARASITIC ANIMALCULE OF THE HUMAN

SKIN.

ON March 30, were read to the Royal Society, some 66 'Researches into the Structure and Development of a newly-discovered Parasitic Animalcule of the Human Skin, the Entozoon folliculorum," by Mr. Erasmus Wilson, Lecturer on Anatomy and Physiology at the Middlesex Hospital.

While engaged in researches on the minute anatomy of the skin and its subsidiary organs, and particularly on the microscopical composition of the sebaceous substance, Mr. Wilson learned that Dr. Gustow Simon, of Berlin, had discovered an animalcule which inhabits the hair follicles of the human integument, and of which a description was published in a memoir contained in the first Number of Müller's Archiv for 1842. Of this memoir, the author gives a translation at full length. He then states that, after careful search, he, at length, succeeded in finding the parasitic animals in question, and proceeded to investigate more fully and minutely than Dr. Simon had done the details of their structure, and the circumstances of their origin and development. They exist in the sebaceous follicles of almost every individual, but are found more especially in those persons who possess a torpid skin; they increase in number during sickness, so as in general to be met with in great abundance after death. In living and healthy persons, from one to three or four of these entozoa are contained in each follicle. They are more numerous in the follicles situated in the depression by the side of the nose; but they are also found in those of the breast and abdomen, and on the back and loins. Their form changes in the progress of their growth. The perfect animal presents an elongated body, divisible into a head, thorax, and abdomen. From the front of the head proceed two moveable arms, apparently formed for prehension: and to the under side of the thorax are attached four pair of legs, terminated by claws. The author distinguishes two principal varieties of the adult animal; the one remarkable for the great length of the abdomen and roundness of the caudal extremity; whilst the other is characterized by greater compactness of form, a shorter abdomen, and more pointed tail. The first variety was found to measure, in length, from the one-100th to the 45th, and the second, from the one-160th to the 109th part of an inch. The author gives a minute description of the ova of these entozoa, which he follows in the successive stages of their develop

ment.

R

BOTANY.

CARBON AND NITROGEN IN PLANTS.

The

MR. RIGGE has communicated to the Royal Society, "A statement of Experiments showing that Carbon and Nitrogen are compound bodies, and are made by Plants during their growth." author, finding that sprigs of succulent plants, such as mint, placed in a bottle containing perfectly pure water, and having no communication with the atmosphere except through the medium of water, or mercury and water, in a few weeks grow to more than double their size, with a proportionate increase of weight of all the chemical elements which enter into their composition, is thence disposed to infer that all plants make carbon and nitrogen; and that the quantity made by any plant varies with the circumstances in which it is placed.

RESPIRATION OF THE LEAVES OF PLANTS.

MR. W. H. PEPYS has detailed to the Royal Society a series of experiments on the products of the Respiration of Plants, and more particularly of the leaves; selecting, with this view, specimens of plants which had been previously habituated to respire constantly under an inclosure of glass; and employing, for that purpose, the apparatus which he had formerly used in experimenting on the combustion of the diamond, and consisting of two mercurial gasometers, with the addition of two hemispheres of glass closely joined together at their bases, so as to form an air-tight globular receptacle for the plant subjected to experiment.

The general conclusions he deduces from his numerous experiments conducted during several years, are, first, that in leaves which are in a state of vigorous health, vegetation is always operating to restore the surrounding atmospheric air to its natural condition, by the absorption of carbonic acid and the disengagement of oxygenous gas: that this action is promoted by the influence of light, but that it continues to be exerted, although more slowly, even in the dark. Secondly, that carbonic acid is never disengaged during the healthy condition of the leaf. Thirdly, that the fluid so abundantly exhaled by plants in their vegetation is pure water, and contains no trace of carbonic acid. Fourthly, that the first portions of carbonic acid gas contained in an artificial atmosphere are taken up with more avidity by plants than the remaining portions; as if their appetite for that pabulum had diminished by satiety.

THEINE IN ILEX PARAGUYENSIS.

RECENT chemical researches have proved that the bitter tonic substance called Theine, found in the leaves of tea, is identical with Caffeine, obtained from the seeds of coffee. On this subject, Liebig re