sibly may have something to do with that meteoric dust which is being continually rained upon us from the spaces of the universe.-12 A, July 13, 1876.

CEPHALOSIPHON AND A NEW INFUSORIAN.

Dr. C. T. Hudson concludes that the Cephalosiphon is a genuine Melicertan, forming its tube from early youth, and is not a temporarily incased Philodine, as had been supposed from having only one antenna. The new infusorian is named Archimedea remex, so called from its frequently assumed corkscrew shape, and from its rows of cilia used as banks of oars. The full-grown Archimedea is about one ninetieth of an inch in length, with a tube of one twenty-fifth of an inch, more or less, in length. It was found attached to Anacharis alsinastrum. The tubes are exceedingly slender, and readily deserted upon the least disturbance. They are, of course, far too long for its inhabitant, which, as a rule, lives in the top of it, though occasionally it backs down nearly to the bottom.-Monthly Microscopical Journal, October,

1875.

THE FRESH-WATER RHIZOPODS.

A large number of contributions to our knowledge of "Fresh-water Rhizopoda" have recently appeared in the Archiv für Mikroscopische Anatomie, and we condense the following from a very complete résumé by Mr. William Archer, who has long been known as an indefatigable student of these lively organisms. As for the name Rhizopoda, taken from the resemblance of the pseudopodia to the roots of a tree, it is manifestly inapplicable to the broad-lobed processes of a Difflugia or Arcella, and quite so to the flow and current of the body of an Amoeba, or the rotating motion of a Hyalodiscus. Hertwig and Lisser have proposed the name Sarcodina (Sarcode organisms), with a division into two groups, Monothalamia and Heliozoa, and Mr. Archer's résumé, so far as published, relates principally to the latter.

The Rhizopods in question have been termed "Freshwater Radiolaria." Haeckel calls them Heliozoa, considering them as unicellular organisms, all the true (marine) Radiolaria being multicellular, and, again, as not possessing a

"central capsule," or structure homologous thereto; the rounded bodies seen in their sarcode, and sometimes regarded as a central capsule, are not to be interpreted as such; nor do they possess structures homologous to the "yellow cells of the Radiolaria." This is also the view of Drs. Hertwig and Lisser, in their memoir in Schulte's Archives, 1874, Supp., and in the main of Mr. Archer. Still, as we know nothing, or at least very little, of the developmental history of the two classes, it is possible that an affinity between Radiolaria and Heliozoa may be demonstrable-demonstrated at present it is not. The Heliozoa, then, are an independent class of unicellular (though sometimes, rarely, multonucleated) organisms. Their fundamental form a sphere, a very few fixed by a stipes. The protoplasm, of which alone the soft part of the body is wholly composed, is differentiated into an endosarc and ectosare, more or less pronounced. In the endosare constantly lie the nuclei; if the nucleus (as mostly) is simple, it is more or less excentric; if there be numerous nuclei, they are irregularly scattered. The ectosarc is characterized by the possession of contractile vacu oles (not yet demonstrable in all species). The pseudopodia, serving both for the capture of nutriment and for locomotion, are thin and filiform, originating all around the superficies of the globular body; sometimes homogeneous, and sometimes granules pass along them slowly up and down. In many of the Heliozoa is an extremely delicate axis, passing down the pseudopodium to the endosare as a strengthening apparatus, but not at all homologous with the spines of the Acanthometrida, as Greef has suggested. In the paper we have alluded to, Mr. Archer considers the two genera of the Heliozoa Askelata, Actinophrys and Actinosphænum. The resemblance between these is considerable, but in the former the nucleus is always single, in the latter there are numerous nuclei; in the latter the two regions, both alveolar, are distinctly marked, in the former the endosarc is homogeneous, passing by degrees into the vacuolar ectosarc.-Quart. Jour. of Mic. Science, July, 1876.

H. BOTANY AND HORTICULTURE.

TREE GROWTH AND THE PRESSURE OF THE BARK.

The influence of the pressure of the bark upon the structure of the annual layers of woody fibre has formed the subject of an excellent memoir by De Vries, who states that while the classic work of Nord binger (Der Holzring, etc., 1870) gives a complete résumé of our knowledge with respect to the connection between the thickness of the annual layers and the pressure of the bark, yet, on the other hand, the phenomena connected with longitudinal incisions still remain to be considered; and he has made a long series of experiments at the Botanical Gardens at Amsterdam, in which he first has diminished artificially the pressure of the bark by longitudinal incisions; and, second, has increased the pressure artificially by enveloping the tree with a tight cord. He has been able to demonstrate, first, that the radial diameter of the woody fibres depends upon the pressure exerted by the bark during their formation; the greater the pressure the smaller the radii of the fibre. Second, the number and the size of the vessels which exist in any woody shell depends upon the pressure exerted by the bark during the formation of the shell: to a greater pressure corresponds a smaller number and a smaller diameter of the vessels.-1 E, XI., 1.

THE ELM OF BOSTON COMMON.

In the Transactions of the Massachusetts Horticultural Society for the year 1876, some interesting remarks are published, made on the occasion of the prostration by a gale of the ancient elm on Boston Common, which event occurred on the 15th of February. Mr. Hovey stated that one of the only two living seedlings of the Charter Oak, and which was now forty years old, was at present standing on his own grounds at Cambridge. Mr. Wilder suggests that a young tree growing very near the roots of the great elm was probably either a seedling or a sucker, and should be planted on this centennial year as a successor to the old tree. Mr.

Cruickshank stated that during the week when the Charter Oak at Hartford was prostrated, a similar event occurred to an oak in Scotland under which the Scottish hero, Sir William Wallace, had once taken refuge. The Rev. Dr. Muzzy stated that the loss of old trees touches our patriotism, and that the Washington Elm at Cambridge was even more precious than the old elm on the Common. A number of remarks were made as to the importance of caring for old trees by cutting off long, dying limbs and encouraging the vigorous buds.-Transactions Massachusetts Horticultural Society, 1876, 84.

ON THE ACCLIMATIZATION OF PLANTS.

Mr. G. F. Waters, in making some general remarks on acclimatizing plants, states that in Waterville, Maine, he had developed a variety of the sweet-corn, which had been grown in a rich soil, having a southeast exposure, abundantly sheltered from the north winds. In successive years its time of ripening was, at first, the middle of October, next the middle of September, next the middle of July, and the fourth year the first of August. In five years it had, therefore, shortened the period of growth from four and a half months to less than two and a quarter months, and it had frequently been gathered for the table in sixty days from planting, while the ears had shrunk from sixteen to eight rows of kernels.

In some experiments on potatoes, the freezing of the tubers before they were dug, according to his experience, seemed to shorten the period required for the maturity of the next gen. eration. He therefore formulates a theory as follows: If to the sun's influence there be added that of the autumn's frosts, checking maturation, and holding the food elements of the embryo where they are best fitted to be taken up in the spring, then we shall have seeds which will germinate still earlier, and as their plants will be longer under the accelerat ing influence of the increasing heat and light of the rays of the sun, they will show better development than their pro genitors. From the discussion ensuing on the reading of Mr. Waters' paper, we gather that the general experience of the members of the society was not wholly favorable to Mr. Waters' theory; Mr. Hovey and Mr. Wilder had both of them but little faith in our ability to acclimate plants indig

enous to a very different climate.-Transactions Massachusetts Horticultural Society, 1876, 70.

AN AGED OAK.

Mr. Amyot gives a very interesting account of the Winfarthing Oak. He states that at the time of the Norman Conquest a forest occupied the spot now known as Winfarthing; and in the reign of Henry III. a large park, well stocked with deer, covered the spot. The old oak is said to have been called "an old oak" in the time of William the Conqueror. Nor does this seem incredible, if we compare the measurements still extant with regard to it. The tree was first measured by Mr. Marsham in 1744, when its circumference was thirty-eight feet and seven inches. Its present circumference being forty feet, shows it to have increased seventeen inches in one hundred and thirty years. In 1820 the circumference of the tree at the middle part of its trunk is stated to have been forty feet. The best estimates that can be made of its age are based upon the average growth of oak-trees in that neighborhood, and show that it can not be less than fifteen hundred years old. - Trans. Norfolk and Norwich Nat. Soc., II., 12.

WAXY MATTER ON BEECH BARK.

A green felty mass, formed on the bark of beech-trees, doubtless through the agency of some insect, was investigated by Flückinger and A. Köpp. It had a greasy feel, and under the microscope exhibited thin cylindrical, bent, and twisted fibres, which readily broke up into smaller pieces. A small quantity of other undeterminable substances accompanying it gave no clew to its origin. Water had but little effect upon it, and the extract was tasteless, and without reaction on litmus. The wax extracted from the crude material with boiling bisulphide of carbon, and purified by repeated crystallizations out of its solution in the bisulphide, formed white scales, which fused at 178° to 180°. Neither its analysis nor its reactions indicated identity with Chinese wax, (Pe-la)-cerotyl-cerotate, but its composition seemed to be that of cerotic acid, obtainable from Chinese wax, although the acid reaction of the solution of cerotic acid was wanting.-18 C, September 1, 1875, 548.