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in altogether wanting a rostellum,* a second of the characteristic features shared by most Orchids which is wanting in this plant, the pollinia being the first. By noticing the peculiar action of the anther-lid in Dendrobium, resulting mainly from the remarkable elasticity of the hinge of the lid (or filament of the anther), we may understand better the structure of the same parts in Pogonia, and shall discover in the slight projection of its opening anther-lid that which, attaining its development in Dendrobium, forms so remarkable and important a feature in its economy.

Mr. Scudder also stated that he had noticed in the middle of the previous month the operations of the minute Platygaster, which attacks the eggs of the canker-worm moth, Anisopteryx vernata Harr. After moving round a long while in search of a suitable place to lay its eggs, using its ovipositor as a sort of feeler, the abdomen is plunged down into the space between three contiguous eggs, and the ovipositor perforates the side of one of them, out of view. The body of the insect assumes a position perpendicular to their exposed surfaces, supported in the rear by the wings, which, folded over the back, are placed against the surface behind, while the hind-legs, spread widely apart, sustain the insect on either side, and the middle pair are placed nearer together in the front; with the fore-legs dangling it remains motionless, with the exception of a slight movement of the antennas, for some three or four minutes, after which it moves off, seldom flying, in search of another place. They were very abundant, eight or ten specimens being frequently seen upon a single bunch of eggs. This parasite was first observed by the late Mr. E. G. Herrick, of New Haven.

Prof. J. Wyman described some of the phases of development in the exterior of the human body, and pointed out some of the resemblances between the limbs of the human embryo and the permanent condition of the limbs of the lower animals. In some human embryos about an inch in length, recently examined by him, he found that the great toe was shorter than the others, and, instead of being parallel to them, projected at an angle from the side of the foot, thus corresponding with the permanent condition of this part in the quadrumana.

Mr. George D. Smith was elected Resident Member.

* It would be interesting in this connection to know whether, as in Cffprlp^i- ftm, the Btigfnuitic surface is trifld, or, as in CephcUanthera grandifiora^ it is bifid ; the Importance of the Icnowledgpe of this fact was not recognized when the ex- amination of the fresh flowers was made.

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December 17, 1862.

The President in the chair.

Mr. A. Agassiz gave an account of the changes in size of the yolk in the eggs of starfishes before segmentation commences.

Dr. J. Wyman stated that since the last meeting he had been able, through the kindness of Prof. Agassiz, to examine another specimen of Python Sebae, and had found a single individual each of the male and female Pentastoma in the lungs.

He also stated that soon afler a recent snow-storm, while the ground was entirely covered, he had made some microscopic examinations of the dust of the outer air, collected on plates of glass covered with glycerine. In addition to particles of mineral dust, probably that of coal ashes and of soot, he had detected spores of cryptogams, starch granules and pollen. Fragments of coniferous and other woods were also found. The objects most unexpected at this season of the year were the grains of pollen. It was suggested whether these might not have been derived from the trees, where they may have been lodged in the crevices of the bark, or other irregularities of the surface, and from time to time detached by the wind.

The Librarian called attention to the very valuable series of works upon Fungi recently purchased from the Library of Mr. C. J. Sprague.

The following persons were elected Resident Members: — Messi-s. T. B. Wales, N. C. Munson, N. A. Thompson, S. P. Riiggles, Samuel Johnson, Jr., Joshua Stetson, John Simmons, STaihaniel Cummings, C. Berkley Johnson, Charles C. Little, Augustus Flagg, N. B. Gibbs, J. D. Ba^es, E. Dale, Benjamin S. Rotch, J. C. Cooper, Amos A. Lawrence.