Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett.

  • Karl Theodor Ernst von Siebold
Date:
1854
Catalogue details

Licence: Public Domain Mark

Credit: Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    pigment,® for the blue, violet and green pigments, seen in the eyes of in- sects and Crustacea, show clearly that the red pigment is not essential to the eye.* CHAPTER V. DIGESTIVE APPARATUS. §11. The Infusoria are nourished, either by taking solid food into the interior of their body, or by absorbing by its entire surface nutritive fluids which occur in the media in which they live. This last mode is illustrated in the Astoma, which have no distinct oral aperture or digestive apparatus. Ry the ingenious experiment first per- formed by Gleichen,(1) of feeding these animals with colored liquids, no trace of these organs could be found. Ehrenberg, who also had observed that they did not eat, regarded their internal vesicles as stomachal organs, which were in connection with the mouth by tubes. The correctness of this opinion, however, has not been verified. Indeed, the genus Opalina<2) refutes it; here the species are quite large and visible to the naked eye, yet an oral aperture can be detected up- on no part of their body, and never do they admit into its interior colored particles. Solid substances found in them cannot be regarded as food. That fluids are here introduced by surface-imbibition is shown by Opalma ranarum ; this animal is found in bile in the rectum of frogs, and assumes a green color. When Opalina requiring only a certain quantity of liquid are placed in water, they quickly absorb it, become greatly swollen, and shortly after die. In such cases, the absorbed liquid is seen as clear, vesicular globules under the surface, and these globules have been taken by Ehrenberg as stomachal vesicles (ventriculi), and by Dujardin as VACUOLAE. §12. Those Infusoria which are nourished by solid food have a mouth at a cer- tain place, and an oesophagus traversing the parenchyma of the body. Through this last the food is received, and is finally dissolved in the semi-liquid parenchyma of the body, without passing through stomachal or intestinal cav- ities. In many cases there is at the end of the body opposite the mouth an anus, through which the refuse material is expelled. But, when this is 3 “ Die Infusionsthierchen,” p. 492. 1 Auserlesene mikroskopische Entdeckungen, 1777, p. 51 *, also, Abhandlung tiber die Saaraen- und Infusionsthierchen, 1778, p. 140. * Some recent researches of Thuret (Ann. d. Sc. Nat. 3rd ser. XIV. 1850) on the reproductive germs of Algae prove that these bodies have red eye- like specks, resembling those seen in the Polygas- trica, but which disappear when the Zoospores at- tach themselves and germination proceeds. The 2 The genus Opalina was first established by Purkinje Valentin. Many species are found in the rectum of frogs, and it is not rare to meet with them in the alimentary canal of Planarieae.f fact is a very interesting one in this connection. — Ed. f [§ 11, note 2.] According to Agassiz (Amer. Jour. Sc. XIII. 1852, p. 425), Opalina is only a larval form of Distoma. — Ed.