The royal natural history . s its shape. The amoeba is CHAR A CTERISTICS. 551 generally found on the ooze of ponds, or the under surface of the leaves of aquaticplants, but especially amongst conferva, in clear gently flowing water. When firstcaught, the animal will appear as a tiny yellowish semitranslucent globular speck,about one-hundredth of an inch in diameter; presently it becomes beaded withrounded projections, some of which grow longer at the expense of others and ofthe body, and may give off one or two branches. By the projection of theseprocesses, or pseudopods, the amoeba moves alon
The royal natural history . s its shape. The amoeba is CHAR A CTERISTICS. 551 generally found on the ooze of ponds, or the under surface of the leaves of aquaticplants, but especially amongst conferva, in clear gently flowing water. When firstcaught, the animal will appear as a tiny yellowish semitranslucent globular speck,about one-hundredth of an inch in diameter; presently it becomes beaded withrounded projections, some of which grow longer at the expense of others and ofthe body, and may give off one or two branches. By the projection of theseprocesses, or pseudopods, the amoeba moves along in the direction of the longerones. Sometimes, writes Leidy, the animal creeps onward in a flowing mannerwith comparatively simple cylindroid form, occasionally emitting a single pseudopodon one side or the other. More commonly, in movement, it assumes a dendroid orpalmate form, or sometimes, diverging from the directly onward course, it becomesmore radiate in appearance. Not unfrequently it assumes more or less grotesque. peoteus animalcule, (highly magnified). shapes, in which almost every conceivable likeness may be imagined. The body,of the amoeba is full of granules, which render it semiopaque, with the exceptionof a thin clear outer hyaline zone, and near the centre is a globular or discoid body,known as the nucleus, composed of a denser protoplasm than that which surroundsit. Division of an amoeba into two is preceded by division of the nucleus. Nearthe latter is a clear spherical space—the contractile vacuole—which graduallyexpands, rather suddenly collapses, and reappears at the same spot, the systole anddiastole being slow and continuous. The contractile vacuole contains a clear liquid,which is expelled on the collapse of the vacuole. This organ probably serves thedouble function of respiration and excretion. The amoeba is omnivorous, but ischiefly vegetarian, and browses on tender leaves, or feeds on diatoms and otheralgse; it surrounds the food-particle or org
Size: 1784px × 1401px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectnaturalhistory, booksubjectzoology
