Vertebrate Embryology: A Text-book for Students and PractitionersG. P. Putnam's sons, 1893 - 640 Seiten |
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Vertebrate Embryology: A Text-Book for Students and Practitioners (Classic ... A. Milnes Marshall Keine Leseprobe verfügbar - 2017 |
Häufige Begriffe und Wortgruppen
adult alimentary canal allantoic allantois amnion Amphioxus aortic arches appear arise artery auditory auricle becomes blastodermic vesicle blastopore blood blood-vessels body cavity brain branchial arch cartilage chick embryo cleft close commencement cranial nerve day Fig decidua diverticulum dorsal surface efferent embryo epiblast epithelial cells epithelium fertilisation fifth folds follicle fore-brain formation formed frog fuse ganglion germinal gill-slits gills glands groove hatching head heart hemispheres hinder end human embryo hyoid hypoblast inner kidney later stages layer length liver lobes longitudinal mandibular median membrane mesenteron mesoblast mid-brain mouth neural notochord olfactory opening optic cup outer outgrowths ovary ovum pair pharynx placenta polar bodies portion rabbit embryo rapidly ridge right side roots segmentation septum sinus spermatozoon spinal cord spinal nerves stalk tadpole thalamencephalon thickened third transverse section truncus arteriosus tube uterine uterus venosus ventral surface ventricle Vertebrates vessels vitelline veins wall Wolffian body Wolffian duct yolk yolk-sac yolk-stalk
Beliebte Passagen
Seite 31 - I have stated in the first chapter, that at whatever age a variation first appears in the parent, it tends to re-appear at a corresponding age in the offspring. Certain variations can only appear at corresponding . ages ; for instance, peculiarities in the caterpillar, cocoon, or imago states of the silk-moth : or, again, in the full-grown horns of 'cattle.
Seite 26 - The study of development has in its turn revealed to us that each animal bears the mark of its ancestry, and is compelled to discover its parentage in its own development ; that the phases through which an animal passes in its progress from the egg to the adult are no accidental freaks, no mere matters of developmental convenience, but represent more or less closely, in more or less modified manner, the successive ancestral stages through which the present condition has been acquired.
Seite 25 - The doctrine of descent, or of Evolution, teaches us that as individual animals arise, not spontaneously, but by direct descent from pre-existing animals, so also is it with species, with families, and with larger groups of animals, and so also has it been for all time ; that as the animals of succeeding generations are related together, so also are those of successive geologic periods ; that all animals, living or that have lived, are united together by blood relationship of varying nearness or...
Seite 93 - The tadpole ceases to feed ; a casting, or ecdysis, of the outer layer of the skin takes place; the horny jaws are thrown off; the large frilled lips shrink up ; the mouth loses its rounded suctorial form and becomes much wider; the tongue, previously small, increases considerably in size. The eyes, which as yet have been small, become larger and more prominent.
Seite 28 - ... history ; yet it is also an undoubted fact, recognised by all writers on embryology, that the record so obtained is neither a complete nor a straightforward one. It is indeed a history, but a history of which entire chapters are lost, while in those that remain many pages are misplaced and others are so blurred as to...
Seite 26 - ... all animals, living or that have lived, are united together by blood relationship of varying nearness or remoteness ; and that every animal now in existence has a pedigree stretching back, not merely for ten or a hundred generations, but through all geologic time since the dawn of life on this globe.
Seite 31 - Moreover, the history of development in different animals or groups of animals offers to us, as we have seen, a series of ingenious, determined, varied, but more or less unsuccessful efforts to escape from the necessity of recapitulating, and to substitute for the ancestral process a more direct method.
Seite 94 - The forelimbs appear, the left one being pushed through the spoutlike aperture of the gill-chamber, and the right one forcing its way through the opercular fold, in which it leaves a ragged hole. The abdomen shrinks; the stomach and liver enlarge, but the intestine becomes considerably shorter than before, and of smaller diameter; the animal now becomes carnivorous.
Seite 583 - Eustachian valve, passes through the foramen ovale into the left auricle, where it becomes mixed with a small quantity of blood returned from the lungs by the pulmonary veins. From the left auricle it...