The Effects of High Hydrostatic Pressures on A Suctorian

Abstract

1. The suctorian Discophrya piriformis Guilcher has been subjected to pressures ranging from 1000 to 15,000 lb./sq.in. (68-1020 atm.). 2. Pressures of 2000 lb./sq.in. and over cause a creasing of the body surface. Except at the higher pressures this occurs some seconds after the application of pressure. 3. Creasing is accompanied by an expansion of the pellicle. At the lower pressures, there is also an expansion of the protoplasmic surface. A comparison may be made with the expansion of the body surface which occurs during feeding. 4. In many cases, and particularly at the higher pressures, the protoplasm later separates from the expanded pellicle. With prolonged treatment it sometimes rounds up, and there is evidence of a loss of volume of the protoplasm. 5. On release of pressure the protoplasm spreads back to the pellicle, usually within a few minutes. The wrinkled and expanded pellicle is then slowly reorganized to its normal shape and size, over a period of many hours.