A General Outline of the Animal Kingdom: And Manual of Comparative Anatomy

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John Van Voorst, 1, Paternoster Row, 1841 - 732 Seiten
 

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Seite 353 - The poor beetle, which we tread upon, In corporal sufferance feels a pang as great As when a giant dies.
Seite 554 - The eye itself differs in many points of structure from that of terrestrial Vertebrata, its organization being of course adapted to bring the rays of light to a focus upon the retina in the denser element in which the fish resides ; the power of the crystalline lens is therefore increased to the utmost extent, and the antero-posterior diameter of the eye-ball necessarily contracted in the same ratio, in order that the retina may be placed exactly in the extremely short focus of the powerful lens.
Seite 169 - ... structure of the penis. The result of our own examination, in more than one species, is different still. We have always found the earthy matter forming a jointed calcareous tube. This tube, which is about the thickness of a surgeon's probe, is composed of rings of calcareous substance connected by membrane, so that viewed externally it is not unlike the windpipe of a small animal.
Seite 717 - ... with each other. The medulla spinalis is surrounded with a network of arteries in the same manner, more especially where it comes out from the brain, where a thick substance is formed by their ramifications and convolutions ; and these vessels most probably anastomose with those of the thorax.
Seite 61 - Paramecium aurelia, if well supplied with food, has been observed to divide every twenty-four hours, so that in a fortnight, allowing the product of each division to multiply at the same rate, 1 6,384 animalcules would be produced from the same stock...
Seite 464 - ... took one the day after the first experiment, and found that the aperture was covered by a thin glutinous lamina, which, somewhat in the manner of a cobweb, unites the two margins of the broken shell. The next day the lamina was, to a certain degree, thickened and more opaque, till, at the expiration of ten or twelve days, the new piece had become quite calcareous. Whilst the Argonaut was in the act of mending the fractures in its shell, I am quite sure that it applied the sails to the shell and...
Seite 211 - ... the blood has passed through the alimentary canal in the ordinary manner, during all which period so much of the blood as remains undigested in the stomach continues in a fluid state. — Leeches are furnished with eight or ten simple eyes, which may be detected by the aid of a magnifying-glass, as a semicircular row of black points, situated above the mouth upon the sucking surface of the oral disc ; this position is evidently calculated to render these organs of use in the discovery of food....
Seite 496 - is far from presenting those complexities of structure that render it so remarkable an organ in Dibranciate Cephalopods. Indeed, it here appears to be reduced to the simplest condition that the organ of vision can assume, without departing altogether from the type which prevails throughout the higher classes. For although the light is admitted by a single orifice into a globular cavity or camera obscura, and a nerve of ample size is appropriated to receive the impression, yet the parts which regulate...

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