Dr. Hayes said that the metal had already been applied for manufacturing purposes in Philadelphia. The price there was $108 a pound.

Dr. W. F. Channing also exhibited half an ounce of this metal, with a piece of silver of the same weight, to show their comparative specific gravities. He also showed some alloys of. aluminium with silver, prepared by Mr. Farmer. For this purpose this metal would probably be found very valuable.

Four hundred and twenty-eighth meeting.

May 27, 1856. ANNUAL MEETING.

The PRESIDENT in the chair.

The President reported from the Council a list of the Fellows, Associate Fellows, and Foreign Honorary Members chosen during the past year. Also a list of those deceased since the last annual meeting, viz. :

The Treasurer, the Committee on Publications, and the Committee on the Library, severally presented their annual reports.

The following gentlemen were elected Fellows, viz. :—

The annual election was held, and the following officers

were chosen for the ensuing year :

JACOB BIGELOW,.
DANIEL TREADWELL,

ASA GRAY,

SAMUEL L. ABBOT,

NATHANIEL B. SHURTLEFF,

President.

EDWARD WIGGLESWORTH,.

Vice-President.

Corresponding Secretary.

Recording Secretary.

Librarian.

Treasurer.

The several Standing Committees were appointed, on nomination from the chair, as follows:

-

Committee of Publication.

JOSEPH LOVERING, LOUIS AGASSIZ,

C. C. FELTON.

Committee on the Library.

AUGUSTUS A. GOULD, BENJAMIN A. GOULD, JR.,

Auditing Committee.

THOMAS T. BOUVÉ,

CHARLES E. WARE.

Professors Treadwell and Lovering and Mr. J. P. Hall were appointed a committee to consider the subject of the meteorological observations of the Academy.

Professor Gray made a brief communication on the placentation of certain Gentianacea, and the variable æstivation of the corolla in certain Scrophulariacea. His former pupil, Mr. Henry James Clark, of Cambridge, had recently shown him that in most of our North American Gentians the ovules are spread over the whole parietes of the ovary, either irregularly or in vertical lines on the veins; and on examination, the same thing was found to occur in Bartonia, Muhl. (Centaurella, Michx.) even more strikingly, the innumerable small ovules being thickly crowded over the whole inner surface of the ovary, just as in Obolaria; and even the somewhat cruciform shape of the transverse section of the ovary of Obolaria is repeated in Bartonia paniculata. These observations may be considered as decisive of the question of the true position, in the natural system, of Obolaria, so long viewed as anomalous; its affinities to the Gentianacea, long ago suggested by Nuttall, and advocated by Professor Gray in the third volume of the Memoirs of the Academy, being now perfectly confirmed. For this very placentation, which was naturally thought to indicate a relationship rather with the Orobanchacea (in which, however, this particular arrangement does not occur), now proves to be a confirmation of its affinity with the Gentianacea.

The only remaining obstacle to this view is the imbricated æstivation of the corolla of Obolaria; a character which Professor Gray could not consider of very great consequence, since a different deviation from the usual convolute æstivation is well known to occur in one tribe of the Gentian Family (the Menyanthea). And as an instance of the occasional breaking down of this character, even in cases where it is generally stable and systematically important, he referred to

the Scrophulariacea, and to some observations made by his pupil, Mr. Clark, several years ago, upon Mimulus, showing that this genus of the Antirrhinidea not rarely has the lobes of the lower lip of the coralla external in æstivation, as in the Rhinanthidea. Professor Gray had recently noticed the same thing in an anomalous still unpublished Penstemon, which presented both modes of æstivation in different flower-buds of the same inflorescence.

The Corresponding Secretary communicated; from the author, the following

"Synopsis of the Cactaceae of the Territory of the United States and Adjacent Regions, by GEORGE ENgelmann, M. D., of St. Louis, Missouri.

"The only Cactus known to Linnæus from the countries north of Mexico was his Cactus Opuntia (Opuntia vulgaris). Long after him, more than forty years ago, Nuttall, the pioneer of West American botany, discovered two Mamillaria and two Opuntia on the Upper Missouri, and again, twenty years later, in California, a new Echinocactus. About ten years ago we became acquainted with numerous new Cactaceæ, in Texas through Mr. F. Lindheimer; in New Mexico through Dr. A. Wislizenus; and in Northern Mexico through the same explorer and Dr. J. Gregg some others (and among them the giant of Cacti) were indicated in the Gila country by the then Lieutenant W. H. Emory. Soon afterwards Mr. A. Fendler collected several new species about Santa Fé. Mr. Charles Wright, a few years later (1849), discovered in Western Texas and Southern New Mexico still other undescribed Cacti.

"But the greatest addition to our knowledge of the Cactaceae of the southern part of the United States was made by the gentlemen connected with the United States and Mexican Boundary Commission, at first under Colonel Graham, and subsequently under Major Emory. Science is indebted principally to Dr. C. C. Parry, Mr. Charles Wright, Dr. J. M. Bigelow, Mr. George Thurber, and Mr. A. Schott, for valuable collections of living as well as dried specimens, and for full notes taken on the spot.

"About the same time, Mr. A. Trécul of France, and after him Dr. H. Poselger of Prussia, traversed Southern Texas and Northern Mexico, collecting many Cactaceae, and increasing our knowledge of this interesting branch of botanical science.

"The Pacific Railroad expeditions since 1853 have opened fields not before explored; and Dr. Bigelow, the botanist and physician of Captain A. W. Whipple's expedition along the 35th parallel, availed himself of these opportunities in a most successful manner; while Dr. F. V. Hayden, almost unaided in his adventurous expedition, has extended our knowledge of the northernmost Cactaceae in the regions of the Upper Missouri and Yellowstone Rivers.

"The last, but by no means least addition, was made in 1854 and 1855, by Mr. Arthur Schott, during the exploration under Major Emory of the country south of the Gila River, known as the Gadsden Purchase.

"Most of the materials brought together by these different explorers have come into the hands of the writer; but few of the discoveries made since 1847 and 1848 have been given to the public;-partly because the material on hand very often was incomplete, and partly because it seemed desirable to publish the whole in an elaborate form with the Reports of the Boundary Commission and those of the Pacific Railroad Surveys. These reports are now in preparation; but the splendid plates which are to illustrate the natural history of these plants cannot be finished for some time; it is therefore deemed advisable now to publish short descriptions of the new species, and systematically to arrange them with those before known.

CACTACEE.

Tribus I. TUBULOSE, Miquel.

Subtrib. 1. PARALLELE. Cotyledones margine hilum versus spectantes, lateribus seminis parallelæ.

I. MAMILLARIA, Haw.

Ovarium baccaque læves. Semina fere exalbuminosa. Cotyledones abbreviatæ, plerumque erectæ, subconnata. Plantæ mamillato-tuberculata; inflorescentia laterali s. verticali.

Subgen. 1. EUMAMILLARIA. Flores ex axillis tuberculorum anni. prioris nunquam sulcatorum: ovarium plerumque immersum versus fructus maturitatem emergens.

1. Polyacantha, Salm.

1. M. MICROMERIS, E. in Bound. Comm. Rep.: parvula, simplex, globosa; tuberculis minimis verrucæformibus confertissimis ; areolis