The thanks of the Academy were voted to Professor Gray for his efficient services as Corresponding Secretary.

Professor Peirce proposed that special meetings of the Academy should be holden on the first Tuesdays in June and July, at four o'clock, P. M.

Voted, that such meetings be holden.

Three hundred and thirty-third meeting.

June 4, 1850.- MONTHLY MEETING.

The PRESIDENT in the chair.

Dr. A. A. Gould declined serving as a member of the Committee of Publication, and Professor Joseph Lovering was nominated by the chair, and unanimously chosen, to fill the

vacancy.

Professor Agassiz presented some new views respecting the coloration of animals. He stated that the coloration of the lower animals living in water depends upon the condition, and particularly upon the depth and transparency, of the water in which they live; that the coloration of the higher types of animals is intimately related to their structure; and that the change of color which is produced by age in many animals is connected with structural changes. He stated that coloration is valuable as an indication of structure; that it is a law universally true of vertebrated animals, that they have the color of the back darker than that of the sides; and that the same system of coloration prevails in all the species of a genus, partially developed in some, but recognizable when a large number of species is examined.

Professor Peirce expressed the opinion, that there are errors in the lunar theory that still remain to be investigated; that occultations cannot be relied on as a means of accurately determining longitude; and that they are of little use for any purpose, except when whole groups of stars, as the Pleiades or Hyades, are taken.

He made some remarks upon the orbit of the comet of 1843, considered as a straight line directed through the sun's

centre.

Three hundred and thirty-fourth meeting.

July 2, 1850.- MONTHLY MEETING.

The PRESIDENT in the chair.

The Corresponding Secretary communicated letters of acceptance from Professor Elias Fries of Sweden, and M. Macédoine Melloni of Naples, recently elected Foreign Members. The latter gentleman states that he has sent to the Academy the first volume of his work, "Sur la Coloration Calorifique," in which he has demonstrated, as he believes, the identity of light and heat.

The Corresponding Secretary also communicated letters from the Secretary of the Royal Institution, the Secretary of the Linnæan Society, the Librarian of the British Museum, and the President of the Academy of Breslau, acknowledging the receipt of various publications of the Academy; and two letters from Petty Vaughan, Esq., recently deceased.

Professor Peirce stated, that Mr. Schubert had discovered that Spica is a double star, one of the component parts of which is invisible. This conclusion was deduced by Mr. Schubert from observations made from 1764 to 1847 inclusive, and was said by Professor Peirce to rest on much stronger grounds than the similar conclusions of Bessel in regard to certain other stars. Spica has an irregular motion in right ascension, and it revolves in fifty years at the distance of one second and a half from the common centre of gravity of the two. This discovery Professor Peirce considered a most remarkable step in the progress of stellar astronomy.

Mr. S. C. Walker exhibited to the Academy a drawing illustrative of the results of experiments made by him on the 4th of February last, to determine the velocity of electricity,

through the telegraphic circuit between Washington and St. Louis, seventeen hundred miles in length. His experiments gave a velocity of a little less than ten thousand miles a second. This result he proposes to test by further experiments on telegraphic lines, in which chemical changes of colors are used, instead of markings made by an electro-magnet. Mr. Walker found that pauses and syllables could be simultaneously transmitted in opposite directions, without interference, in the telegraphic circuit, in the same manner as they are in air.

Professor Agassiz stated that he had ascertained that there are certain animals, capable of performing all the great functions of animal life, which consist entirely of cells. He referred, in illustration of his remark, to the genus Coryne of the Polypoid Medusa, found in Boston harbor. He distinguished the cells of which the tentacles of these animals are composed into three kinds, epithelian, lasso, and locomotive cells. The tentacles, which consist of two cylindrical bodies, one within the other, tapering to a point, and without any cavities, are composed entirely of such cells. The epithelian cells cover the whole surface of the tentacles. The individual lasso cells throwing out their inner cylindrical body, the tentacles are converted into stems, with long, lateral threads, for catching small animals. By the contraction of their inner or locomotive cells, they are reduced to one tenth of the length they have when elongated. The locomotive cells were stated by Professor Agassiz to undergo endosmosis and exosmosis, accompanied by a change of form in the individual cells which constitute the inner cylinder of the tentacle, and in that change, to become organs of locomotion. The apparent fibres, described by some writers, were said by Professor Agassiz to be merely elongated cells.

Professor Peirce and Dr. Walter Channing made some further remarks in regard to the cause of the elongation of the cells.

After a discussion of considerable length, in which Mr.

Guyot, Mr. B. A. Gould, Jr., Professor Agassiz, and the President took part, on the importance and practicability of introducing a uniform system of thermometrical and barometrical notation in all countries where science is cultivated, it was, on motion of Mr. Guyot,

"Voted, That a committee be appointed to consider the expediency of recommending the adoption of the centigrade thermometrical scale, and the metrical barometrical scale at the meteorological stations in Massachusetts.

"Voted, That Mr. Guyot, Professor Agassiz, Professor Peirce, Professor Lovering, and Mr. B. A. Gould, Jr. be that committee."

Professor Agassiz made some remarks respecting the structure of the egg. He stated that no two portions of the egg between the centre and the periphery have the same structure; that the yolk does not consist of homogeneous cells; and that it is not a store of nutritious matter to feed the young animals, but that it is a living, organized being.

On motion of Professor Peirce, it was voted that a monthly meeting of the Academy be held on the first Tuesday in August, at four o'clock, P. M.

On motion of Mr. B. A. Gould, Jr., it was

"Voted, That a committee be appointed to address a memorial to the Senate and House of Representatives of the United States, on the subject of attaching a corps of scientific men to the commission for running the boundary line between the United States and Mexico."

Professor Agassiz, Professor Peirce, and Mr. B. A. Gould, Jr., were appointed a committee for that purpose.

Three hundred and thirty-fifth meeting.

August 6, 1850.- MONTHLY MEETING.

The PRESIDENT in the chair.

The Corresponding Secretary read a letter of acceptance from Professor Bischoff of Giessen, recently elected a Foreign Member of the Academy.

Professor Agassiz communicated a paper on Spermatozoa by Dr. Burnet, of which he gave a brief abstract. He highly commended the paper, as establishing new and important views, and evincing uncommon qualifications on the part of its author for such researches.

On motion of Professor Agassiz, it was referred to the Committee of Publication.

Professor Agassiz stated that he had ascertained that catfishes, and the whole family of Silurida, to which they belong, have a sub-cutaneous cavity behind the humerus, and outside of the peritoneum and the muscular walls of the abdomen, into which protrude portions of the liver, and sometimes the air-bladder and kidney. He also stated that these animals have lateral holes for the admission of water into the interior of their bodies.

Professor Agassiz exhibited a part of the skin of a Bonito, caught off Nahant, which presented a remarkable peculiarity in the form of its scales. At first sight, the animal seemed to offer the anomalous phenomenon of ctenoid and cycloid scales occurring upon the same individual; but, on further examination, the scales were found to be a new type, intermediate between the ctenoid and the cycloid, the serratures being merely marginal, and not extending over the posterior surface. He also called attention to some dark, longitudinal stripes, which at first appeared to militate with the views he had brought before the Academy at a late meeting, respecting the connection between the coloration and the structure of animals. On examining them more carefully, however, each stripe was found to originate at the base of one of the finlets of the tail.

Professor Agassiz, in reply to a question of the President, stated that the shrill noise heard on suddenly drawing a catfish out of the water is occasioned by the escape of air from the air-bladder through the pharynx; and, in reply to a remark of Dr. Gould, he stated that a somewhat similar explanation is applicable to the noise made by the drum-fish