Methods of Study in Natural HistoryMifflin, 1891 - 319 páginas |
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Términos y frases comunes
ab-oral region Acalephs Acephala adult AGASSIZ Animal Kingdom Articulates Astræans Baer belong bilateral symmetry Birds body branch buds called cavity cells centre character classification common compared complication of structure condition connected Coral Reefs corresponding Crinoids Crustacea Ctenophora Cuvier disk distinct divided divisions Echino Echinoderms ELIZABETH CARY AGASSIZ Embryology existence external facts Families Fishes Genera Genus geological geological period germ gills gradation gradually groups growth highest Holothurians Hydroid idea individual inner sac instance investigation Jelly-Fish kind large number less Linnæus living LOUIS AGASSIZ lower lowest mals Mammalia mesoblast mode Mollusks mouth natural naturalists Ophiuran oral region organs peculiar period phases Polyps present relation representatives Reptiles resemblance scientific Sea-Urchin seen shell side Silurian Species stage Star-Fish stem Strobila succession surface tentacles tion transverse true ture variety Vertebrates wall whole Winged Insect Worms yolk young zones
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Página 23 - I have devoted my whole life to the study of Nature, and yet a single sentence may express all that I have done. I have shown that there is a correspondence between the succession of Fishes in geological times and the different stages of their growth in the egg, — this is all.
Página 123 - Does not every member of the crow family caw, whether it be the jackdaw, the jay, or the magpie, the rook in some green rookery of the Old World, or the crow of our woods, with its long, melancholy caw that seems to make the silence and solitude deeper ? Compare all the sweet warblers of the songster family — the nightingales, the thrushes, the mockingbirds, the robins; they differ in the greater or less perfection of their note, but the same kind of voice runs through the whole group. These affinities...
Página 318 - To me the fact that the embryonic form of the highest Vertebrate recalls in its earlier stage the first representatives of its type in geological times and its lowest representatives at the present day, speaks only of an ideal relation, existing not in the things themselves, but in the mind that made them.
Página 42 - when scientific truth must cease to be the property of the few, when it must be woven into the common life of the world...
Página 160 - ... laid. And it is now proved, beyond a doubt, that no reef-building coral can thrive at a depth of more than fifteen fathoms, though corals of other kinds occur far lower, and that the dead reef-corals, sometimes brought to the surface from much greater depths, are only broken fragments of some reef that has subsided with the bottom on which it was growing. But though fifteen fathoms is the maximum depth at which any reef-builder can prosper, there are many which will not sustain even that degree...
Página 166 - But these also have their bounds within the sea : they in their turn reach the limit beyond which they are forbidden by the laws of their nature to pass, and there they also pause. But the Coral wall continues its steady progress ; for here the lighter kinds set in, — the Madrepores (p. 107), the Millepores, and a great variety of Sea-Fans (p. 1G7, below) and Corallines, and the reef is crowned at last with a many-colored shrubbery of .low feathery growth.
Página 122 - ... cat as its stately and majestic form does to the smaller, softer, more peaceful aspect of the cat. Yet notwithstanding the difference in their size, who can look at the lion, whether in his more sleepy mood, as he lies curled up in the corner of his cage, or in his fiercer moments of hunger or of rage, without being reminded of a cat ? And this is not merely the resemblance of one carnivorous animal to another; for no one was ever reminded of a dog or wolf by a lion. Again, all the horses and...
Página 34 - Mollu.sks ; for, though the collector* do not put up their specimens with any intention of illustrating this peculiarity, they instinctively give them the position best calculated to display their distinctive characteristics, and to accomplish this they necessarily place them in such a manner as to show the sides. In Articulates there is also a longitudinal axis of the body and a bilateral symmetry in the arrangement of parts; the head and tail are marked, and the right and left (ides are distinct.
Página 161 - How it happens that such a being, which we know is immovably attached to the ground, and forms the foundation of a solid wall, was ever able to swim freely about in the water till it found a suitable resting-place, I shall explain hereafter, when I say something of the mode of reproduction of these animals. Accept, for the moment, my unsustained assertion, and plant our little coral on this sloping shore, some twelve or fifteen fathoms below the surface of the sea. The internal structure of such...