Proceedings of the Boston Society of Natural History, Band 4Boston Society of Natural History., 1854 |
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Andere Ausgaben - Alle anzeigen
Häufige Begriffe und Wortgruppen
Academy of Natural American animal appearance Ayres Bay of Fundy beaks belonging birds body bones Bost Boston Bouvé branchial Burnett C. T. Jackson Cabinet Cabot calcareous cells coal coast color Coprolites Crustacea Curator CYCLAS deposit Desor diam diameter donation dorsal Durkee eggs Europe exhibited fathoms feet fish formation fossil genus Gould H. R. Storer inches insects Isaac Lea Lake Superior length less London Massachusetts Mastodon mineral Mollusk muscles muscular Natural History Natural Sciences nearly Nobis observed oral circle Pamph Philadelphia plants plates posterior posticè presented President PROCEEDINGS B. S. N. H. Prof rays remarkable Report resembles rocks S. N. H. Proc Sandhill Crane Sandstone seen shale shell side Société Géologique Society were voted species specimens Stigmaria Stimpson strata suckers surface Synapta teeth tentacula tenuis testâ thick tion transverse transverse processes tubes umbonibus Whooping Crane William Stimpson Wyman
Beliebte Passagen
Seite 387 - Aphididae, on the other hand, the developing germ derives its nutritive material from the fatty liquid in which it is bathed, and which fills the abdomen of the parent. The conditions of development in this respect are here, therefore, more like those of the Mammalia, and the whole parent animal may be regarded in one sense as an individualized uterus filled with germs ; for the digestive canal with its appendages seems to serve only as a kind of laboratory for the conversion of the succulent liquids...
Seite 116 - THE general idea respecting the origin or cause of stratification, as expressed in geological text-books, or as inferred from the writings of geologists, seems to be this : that strata, or the so-called divisions of sedimentary matter, have been produced either by an interruption of deposition, or a change in the quality of the material deposited. This idea is well illustrated by the deposition of matter by tides or inundations, its subsequent consolidation, and a renewed deposition on the plane...
Seite 116 - ... and that too by divisional planes in some cases not at all coincident with any division of the materials, although this is apt to take place. The strata so produced were in some instances exceedingly perfect and beautiful, not altogether horizontal, but slightly curved, and in some degree conforming to the shape of the funnel. The production of...
Seite 385 - These egg-like bodies consisted either of single nucleated cells, of sVooth of an inch in diameter, or a small number of such cells enclosed in a simple sac. These are the germs of the third generation...
Seite 116 - I do not dispute ; but that there are other causes which tend to produce and have produced stratification, equally extensive and varied, is, I think, clearly shown by the following observations : My attention was first drawn to the subject during the past summer, while engaged in the analysis of soils. By the process adopted, the soil was washed upon a filter for a considerable number of days, in some cases for a period as long as two weeks, and subsequently dried at a temperature of 250° F.
Seite 385 - These are the germs of the third generation or colony, and they increase pari passu with the development of the embryo in which they are formed, and this increase of size takes place, not by the segmentation of the primitive cells, but by the endogenous formation of new cells within the sac. After this increase has continued for a certain time, these bodies appear like little oval bags of cells, — all the component cells being of the same size and shape, — there being no one particular cell which...
Seite 117 - The strata here vary from the fraction of an inch to an inch in thickness; they are also covered with mud-cracks, and the various markings which are usually found upon a shore or beach. In other portions of the valley we have strata divisions, occasioned by the lines which separate materials differing either in quality or nature; as...
Seite 389 - This germ-power may be extended by gemmation or by fission, but it can be formed only by the act of generation, and its play of extension and prolongation by budding or by division must always be within a...
Seite 308 - This is gradually developed by the aggregation of cells, and when about l-25th of an inch in length, its cavity (the pulp-cavity) is occupied with a network of blood-vessels. The growth after this is more rapid and determinate. The epithelial cells covering the apex of the papilla become lineally arranged, and fusing together, form fibres, which, when filled with calcareous salts, constitute the intimate structure of the enamel. This enamel is formed very early, and...
Seite 310 - ... after being irritated and annoyed in its cage, in moving suddenly accidentally struck one of its fangs into its own body ; it soon rolled over and died as any other animal would have done. Here, then, we have the remarkable, and perhaps unique physiological fact, of a liquid secreted directly from the blood, which proves deadly when introduced into the very source (the blood) from which it was derived ! With the view of ascertaining the power and amount of this poison, Dr.