"Certain facts admit of no dispute; such as the existence of a vig. orous hydra attached to a solid substance, with long flowing silky tentacula; an alteration in the figure of the body, or the formation of an embryonic roll of Medusa on the disc; the gradual maturity of each Medusa and its liberation from the roll; the disappearance of the orig. inal tentacula of the hydra; the emerging of a new circle of tentacula from a smooth fleshy bulb, sustaining the embryonic roll, as the former are obliterated, and as the Medusæ approach maturity; the evolution of this fleshy bulb as a perfect hydra, along with their departure, which becomes the parent of progeny by gemmation, and its permanence as an independent animal." (p. 122-3.)

"All the Medusa in the embryonic roll are separate and distinct animals. Each is in close application to that which is next below, if itself be uppermost, or lies between two if intermediate. The proboscis is outermost if the individual be uppermost in the roll; thus all lie in the same direction, the proboscis outermost, as the Medusa escapes, from the next left behind. When the last remains in adhesion to the fleshy bulb, its proboscis projects outwards also. Thus the under surface of the embryo is always outwards, while a portion of the roll." (p. 124.)

"Although by repeated long, and painful observation, I have endeavored to learn the history of the Hydra tuba and the Medusa originating from it, my purpose has been but partially attained. I have selected many individuals, and I have chosen colonies of both, to discover whatever changes they should undergo. The hydra grew, it fed, it bred, its existence was long. The Medusa lived, it neither fed nor bred, its existence was infinitely shorter; nor did it undergo the smallest change from the first moment of liberation for fifty-five days. Its life could not be protracted, on any occasion, beyond sixty days. Between the form and habits of these two animals there is not the smallest correspondence." (p. 128.)

2. Recherches sur les Animaux Fossiles; par L. DE KONINCK. Liége, 1847. Première Partie, Monographie des genres Productus et Chonetes. 4to, illustrated by 20 plates. (Ann. and Mag. Nat. Hist., ii Ser., i, 457, 1848.)-This is the first of a series of works entitled, 'Researches on Fossil Animals;' it contains monographs of the genera Productus and Chonetes. The series is intended to supply the geologist and naturalist with complete monographs of different genera, so as to embody in one work all the species of a genus which are now more or less distributed through many periodicals, memoirs and transactions of societies. The first part contains a list of 107 works and memoirs to which the author has referred in the subsequent pages. To this succeeds an historical introduction and observations on the generic characters, with a classification of the species. A detailed description of each species is given, to which is appended a very complete synonymy. From the geological and geographical distribution which follows we extract a few notes. The number of species of Productus described amounts to 62, of which 4 are Devonian, 47 Carboniferous, 10 Permian, and 1 Triassic. Of the 47 Carboniferous species, 35 only are found in the lower divisions.

Not any species belongs exclusively to the middle division, although 7 are common to the lower and middle portions, viz., P. margaritaceus, undiferus, Flemingii, pustulosus, Keyserlingianus, aculeatus, mesolobus. The P. carbonarius is found only in the upper division. The P. cora, semireticulatus, scabriculus and punctatus appear to have lived from the commencement to the close of the carboniferous period.

It is interesting to observe that all the Devonian species have common general characters, and may be arranged in the same group (Caperati): a similar remark also applies to the Permian species, which, with the exception of three, are nearly all comprised in the group (Horridi), so that the latter group is almost composed of Permian species, the P. Orbignianus, P. Verneuilianus, being the only carboniferous forms; and it is not a little singular, in consulting the table of classification (page 29), to find that the Permian species have a much greater affinity with the Devonian than with the carboniferous, notwithstanding the considerable period which must have elapsed between their development.

Under the geological distribution of the genus Chonetes, we find there are 23 species known at present, which number may probably be increased when the fossiliferous deposits of America, New Holland and Asia are more explored. Nevertheless the geological results to which the known species lead us are deserving of notice. From the observations of M. de Koninck it appears (contrary to the opinion generally admitted), that with the exception of one, not any of the 23 species pass from one system to another, or even from the lower to the upper beds of the same system.

E. G. SQUIER and E. H. DAVIS, M.D. Ancient Monuments of the Mississippi Valley; comprising the results of extensive original Surveys aud Explorations. 1 vol. imperial 4to. Subscription price, $10.

C. PICKERING, M.D. The Races of Men and their Geographical Distribution : forming the xi. volume of the Reports of the United States Exploring Expedition. SEARS C. WALKER. Ephemeris of Neptune for the Opposition of 1848: Smithsonian Contributions to Knowledge. 8 pp. 4to.

R. CHAMBERS, Esq. Ancient Sea Margins, as Memorials of Changes in the Relative Level of Sea and Land. 8vo, 338 pp. with maps and illustrations. Edinburgh and London, 1848.

C. CAMPBELL COOPER. Identities of Light and Heat, of Caloric and Electricity. 96 pp. 8vo. 1848. Philadelphia: Grigg & Elliott. 75c.

MEMOIRS OF THE GEOLOGICAL SURVEY OF GREAT BRITAIN, and of the Museum of Practical Geology in London, vol. ii, part ii, 8vo, pp. 387 to 720; with numerous plates of Mines, Machinery and Fossils. London, 1848. Contains the following Memoirs :

On the Vegetation of the Carboniferous Period as compared with that of the present day;-On some peculiarities in the Structure of Stigmaria; and Remarks on the Structure and Affinities of some Lepidostrobi; by Dr. Hooker, F.R.S., &c. On the Asteriadæ found fossil in British strata ;-On the Cystidea of the Silurian rocks of the British Islands; by Prof. E. Forbes.

First report on the coals suited to the Steam Navy; by Sir H. De la Beche. An experiment on the influence of a weak voltaic current upon matter;-Notices of the history of the lead mines of Cardiganshire; by R. Hunt.

On the mining district of Cardiganshire and Montgomeryshire; by Warrington W. Smyth.

On the composition of some of the Limestones used for Building Purposes, especially on those employed in the erection of the New Houses of Parliament; by T. Ransome and B. Cooper.

Produce of lead ore and lead in the United Kingdom for the years 1845 and 1846.-Produce of lead ore and lead for 1847.

W. F. VAN AMRINGE. An investigation of the theories of the Natural History of Man, by Lawrence, Prichard, and others. 8vo. New York, 1848.

DESHAYES. Mollusques de l'Algerie, 4to, in livraisons of 4 to 5 leaves of text, and six colored plates. 16 fr. each livr. 12 livrs. are on sale; 10 will appear each year.

L'ABBE D. DUPUY. qui vivent en France.

LECOQ et LAMOTTE.

Histoire Naturelle des Mollusques terrestres et d'eau douce

Catalogue Raisonné des Plantes Vasculaires du plateau

central de la France. Paris, 1847. 1 vol., 8vo. 6 fr.

E. RENOU. Geologie de l'Algerie, with descriptions of fossils by Deshayes. 1 fasc., 25 fr. The second will soon appear, and will contain the descriptions of the

fossils.

B. CHARLARD and O. HENRY. Analyse chimique des eaux qui alimentent les fontaines publiques de Paris. 3 fr.

LAURENT. Precis de Cristallographie, suivie d'une méthode simple d'analyse au chalumeau. Paris, 1847. 1 vol. in large 18mo, with 175 figures in the text. 2 fr. 25c.

E. F. GLOCKER. Generum et specierum mineralium secundum ordines naturales digestorum Synopsis, etc. 348 pp. 8vo. Halæ Saxonum, 1847.

MEMOIRS OF THE AMERICAN ACADEMY, BOSTON, new ser., vol. iii-Account of the nebula in Andromeda; G. P. Bond.-Account of the nebula about Orionis ; W. C. Bond.-Method of computing the ratio of a comet's distances from the earth; G. P. Bond.

PROC. BOST. Soc. NAT. HISTORY.--JAN. 5, 1848. Motella, a genus of fish found in the waters of North America; Storer.-Jacksonite, a new mineral; J. D. Whitney.-JAN. 19. Vegetation of Anthracite; J. E. Teschemacher.-FEB. 2. Development of an Echinaster; Desor.-Experiments on animals with chloroform; Desor.-FEB. 15. Development of embryo starfish; Desor.-Infusorial deposits found at the mouths of rivers in the Southern States, caused by the influx of infusoria with the tide, which the freshwaters destroy; H. D. Rogers.-Eggs of Eolis; Desor.-MARCH 15. On water in igneous minerals and metamorphic action.APRIL 19. Water tubes in fishes; Agassiz-JUNE 7. New species of American shells (of Succinea, 2 species, Helix 5, Pupa 2, Cylindrella 2); A. A. Gould.— The American oyster-catcher a different species from the European; Cabot.— JUNE 21. On a peculiarity in the anatomy of a Leuciscus; Ayres.

ANNALES DES SCIENCES NATURELLES. -FEVRIER, 1848. Researches on corals (continued); M. Edwards and J. Haime.—Organization and Development of the Linguatula; Van Beneden.-Anatomical researches on the exterior branchiæ of the Sialis lutarius; L. Dufour.—Natural classification of the Gasteropodous Mol. luscs; M. Edwards.-On the liver of the vertebrata; N. Guillot.-Mode of fecundation in the Enothera; M. W. Hofmeister.-On the ovule and grain of the Acantheæ; J. E. Planchon.-On the Droseraceæ ; J. E. Planchon.—Propagation of the Rhizocarpeæ; C. Nægeli.—On the Azolla; G. Mettenius.-Mycological fragments; J. H. Léveillé.

OFVERSIGT AF KONGL. VET.-AKAD. FÖRHANDLINGAR, 1847.-Includes the following, on Natural History topics :-p. 5. New Alge from Mexico; Agardh.—p. 54. Specific gravity of Zircon; Svanberg.-p. 70. Neolite, a new mineral; Scheerer.-p. 85. Aphthonite, a new antimonial sulphuret of copper and silver; Svanberg. p. 162. A new goniometer; Wallmark.-On the teeth and uncini of molJusca, with figures and descriptions of these appendages in over 80 species of different genera; Loven.

INDEX TO VOLUME VI.

Adams, C. B., on a fractured and repaired Ar. Astringent substances for tanning, mode of

Gray's Genera Illustrata, 300.

Ralfs' British Desmideæ, 302.

Botany of New England, E. Tuckerman, 224.
British Association, notice of meeting, 1848,
445.

|| Brocklesby, J., influence of color on dew, 178.
59

SECOND SERIES, Vol. VI, No. 18.-Nov., 1848.

Dalyell, J. G., work on rare and remarkable

Burr, E. F., on the Neptunian theory of animals, noticed, 452.

Carices America, &c., by H. P. Sartwell, no- Desmides, British, J. Ralfs on, noticed, 302.