. The microscope and its revelations. the centre towards the periphery of the body, and then carrying itback to the central mass, into whose substance it seems to befused as soon as it lias discharged any indigestible material it mayhave contained, which is got rid of through the mouth. Every partof the protoplasmic reticulation is in a state of incessant change,which serves to distribute the nutrient material that finds its wayinto it through the walls of the digestive vesicles ; but no regularci/closis (like that of plants) can be observed in it. Besides the digestive vesicles, vacuoles fill
. The microscope and its revelations. the centre towards the periphery of the body, and then carrying itback to the central mass, into whose substance it seems to befused as soon as it lias discharged any indigestible material it mayhave contained, which is got rid of through the mouth. Every partof the protoplasmic reticulation is in a state of incessant change,which serves to distribute the nutrient material that finds its wayinto it through the walls of the digestive vesicles ; but no regularci/closis (like that of plants) can be observed in it. Besides the digestive vesicles, vacuoles filled with clear fluid may be distin-guished, alike in the central protoplasmic mass, and in its extensionsas is shown in the centre of fig. 587. There is no contractile peculiar tentacle of Xoctiluca is a flattened whip-like fila-ment, gradually tapering from its base to its extremity, the twoflattened faces being directed respectively towards and away fromthe oral aperture. When either of its flattened faces is Fi<;. 589.—Pair of digestive vesicles of Nocfiltica lying in course of exten-sion of central protoplasmic mass, a, to form peripheral reticulation,b, and containing remains of Alga-. (Magnified 4HO diameters.) shows an alternation of light and dark spaces, in every respectresembling those of striated muscular fibre, except that the clearspaces are not subdivided. l?ut when looked at in profile, it is seenthat between the striated band and the aboral surface is a layer ofgranular protoplasm. The tentacle slowly bends over towards themouth about five times in a minute, and straightens itself still moreslowly, the middle portion rising first, while the point approachesthe base, so as to form a sort of loop, which presently seems probable that the contraction of the substance forming thedark bands produces the bending of the filament; whilst, whenthis relaxes, the filament is straightened again by the elasticity ofthe granular laye
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
