An Introduction to the Study of ZoologyD. Appleton, 1920 - 371 pagini |
Alte ediții - Afișează-le pe toate
An Introduction to the Study of Zoology, Illustrated by the Crayfish Thomas Henry Huxley Vizualizare completă - 1895 |
An Introduction to the Study of Zoology, Illustrated by the Crayfish Thomas Henry Huxley Vizualizare completă - 1902 |
An Introduction to the Study of Zoology, Illustrated by the Crayfish Thomas Henry Huxley Vizualizare completă - 1906 |
Termeni și expresii frecvente
abdomen abdominal appendages abdominal somite alimentary canal ambulatory limbs Amurland animals antenna antennule aperture appears artery arthrobranchiæ Astacine Astacus fluviatilis Astacus torrentium attached basal joint blastomeres blood body branchiæ branchial cavity branchiostegite carapace cardiac cavity cephalothorax cervical groove chelate chitinous convex corpuscles coxopodite cray Crustacea cuticle cuticular division ecdysis Écrevisses edge endopodite English crayfish epiblast epipodite exopodite exoskeleton eyestalk fact female filaments fluviatilis.-A forceps front ganglia ganglion gastrolith genus gills give rise green gland hind-gut hinder hypoblast inner integument lateral leptodactylus less lobster longitudinal male mid-gut morphological muscle muscular nerve fibres nobilis noble crayfish nucleated cells nuclei organs ossicle outer pairs pleura podobranchiæ portion posterior prawns present pyloric region ridge rostrum segments septal lines setæ side somite species spermatozoa spines sternal sternum stomach structure substance surface swimmerets telson tergal tergum terminal thoracic thoracic limbs thoracic somite tissue transverse wall yelk zone
Pasaje populare
Pagina vi - Whoever will follow these pages, crayfish in hand, and will try to verify for himself the statements which they contain, will find himself brought face to face with all the great zoological questions which excite so lively an interest at the present day.
Pagina 89 - ... proved that consciousness is wholly unnecessary to the carrying out of many of those combined movements, by which the body is adjusted to varying external conditions.
Pagina 85 - However changeful in the contour of its crest, this wave has been visible, approximately in the same place and with the same general form, for centuries past. Seen from a mile off, it would appear to be a stationary hillock of water. Viewed closely, it is a typical expression of the conflicting impulses generated by a swift rush of material particles. " Now, with all our appliances, we cannot get within a good many miles, so to speak, of the living organism.
Pagina 5 - Crayfishes,' which constitutes the last. I will make a short extract from each of these chapters in order to define more exactly the beginning and end of our subject. In Chapter I. we are introduced to the crayfish family thus:— It is a matter of common information...
Pagina 85 - Seen from a mile off, it would appear to be a stationary hillock of water. Viewed closely, it is a typical expression of the conflicting impulses generated by a swift rush of material particles. " Now, with all our appliances, we cannot get within a good many miles, so to speak, of the crayfish. If we could, we should see that it was nothing but the constant form of a similar turmoil of material molecules which are constantly flowing into the animal on the one side, and streaming out on the other.
Pagina 14 - In fact, every art is full of conceptions which are special to itself ; and, as the use of language is to convey our conceptions to one another, language must supply signs for those conceptions. There are two ways of doing this : either existing signs may be combined in loose and cumbrous periphrases; or new signs, having a well-understood and definite signification, may be invented. The practice of sensible -people shows the advantage of the latter course ; and here, as elsewhere, science has simply...
Pagina 4 - ... knowledge, which is understood by Natural History ; while a few have reached the purely scientific stage, and, as Zoologists and Botanists, strive towards the perfection of Biology as a branch of Physical Science. Historically, common knowledge is represented by the allusions to animals and plants in ancient literature ; while Natural History, more or less grading into Biology, meets us in the works of Aristotle, and his continuators in the Middle Ages, Kondoletius, Aldrovandus, and their contemporaries...
Pagina 291 - A species, in the strictly morphological sense, is simply an assemblage of individuals which agree with one another, and differ from the rest of the living world in the sum of their morphological characters ; that is to say, in the structure and in the development of both sexes.
Pagina 346 - And it is well to reflect that the only alternative supposition is, that these numerous successive and coexistent forms of insignificant animals, the differences of which require careful study for their discrimination, have been separately and independently fabricated, and put into the localities in which we find them. By whatever verbal fog the question at issue may be hidden, this is the real nature of the dilemma presented to us not only by the crayfish, but by every animal and by every plant...
Pagina 84 - ... expelled in new combinations. " The parallel between a whirlpool in a stream and a living being, which has often been drawn, is as just as it is striking. The whirlpool is permanent, but the particles of water which constitute it are incessantly changing. Those which enter it on the one side are whirled around and temporarily constitute a part of its individuality; as they leave it on the other side, their places are made good by new comers.