. The biology of the protozoa. Protozoa; Protozoa. 222 BIOLOGY OF THE PROTOZOA continues and at the same time minute buds of protoplasm appear at the bases of these disappearing membranelles. These buds grow pari passu with the dwindling motile organs until finally the latter are entirely absorbed and the buds have developed into functional membranelles. In the same way each cirrus is replaced by a new growing bud quite regardless of the position in anterior or posterior half. Undulating membranes are similarly withdrawn and replaced by new ones so that the young cells formed by division of th
. The biology of the protozoa. Protozoa; Protozoa. 222 BIOLOGY OF THE PROTOZOA continues and at the same time minute buds of protoplasm appear at the bases of these disappearing membranelles. These buds grow pari passu with the dwindling motile organs until finally the latter are entirely absorbed and the buds have developed into functional membranelles. In the same way each cirrus is replaced by a new growing bud quite regardless of the position in anterior or posterior half. Undulating membranes are similarly withdrawn and replaced by new ones so that the young cells formed by division of the meta- morphosing parent cell receive a full set of new motile organs com- mensurate with the size of the young organisms. The phenomenon. Fig. 112. — Chilodon uncinatus. New mouth and basket replacing the old ones prior to cell division. () New mouth and basket; () old mouth and basket before degeneration and disappearance; () new mouth and basket for the pos- terior individual after division. (After MacDougall.) is very striking in forms with giant cirri such as the jumping types of Euplotidae—Diophrys or Uronychia. In the latter genus the great posterior cirri are the most conspicuous organs of the cell (Fig. 111). The buds which are to grow and replace them are appar- ent before there is other external evidence of the approaching division and even before the nucleus has concentrated into its divi- sion form. At the same time similar buds appear in the division zone, that which is destined to form the giant-hooked cirrus appears first and is always larger than the others which appear one after the other according to ultimate size. Owing to their minute size it has not been determined whether or not the individual cilium is. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Calkins, Gary N.
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