The Microscope Volume 8; An Illustrated Monthly Designed to Popularize the Subject of Microscopy (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1888 Excerpt: ...gave a few convulsive turns, and in three minutes from the time of settling, the first portion of its future dwelling place was distinctly visible (fig. 2. Harris suggests that the reason for the movements noted might be a divesting of the rotifer of a very thin and hyaline pellicle, and sees no reason why this would clash with the theory that the adultt ube is a secretion, since it would assist the flow of the fluid in a proper direction for the purpose it has to serve. Following these movements the rotifer retreats within the cup-like tube, assumes the form of a puffball, and remains apparently quiescent for some time; hardly perceptible changes are, however, going on, (fig. 3.) Four hours later, the organism is visibly enlarged, the cilia have become arranged parallel to each other, and protrude like a small bush, (fig. 4.) These are afterwards absorbed, and an hour later partly developed arms are seen (fig. 5.) After this development goes on and is completed by the following morning. The development is not always the same in point of time in different individuals, one act being, perhaps, prolonged, while another is greatly shortened. As to the length of time after birth when reproduction will take place, a series of observations gave the average as 6J days. The largest number produced by one individual was five; the smallest three, --more frequently four completed the progeny. While the male of this rotifer has not been discovered, Harris found one individual with a pear-shaped cavity near the angle where the posterior portion rapidly narrows; and in this pace were bodies in rapid motion, and which may have been spermatozoa. This creature did not settle down like the others, but led a wandering life; it increased but slightly in size, and its devel...