Y. Okada, Naba, Hyogo-Ken
Oct 1, 1928
Citations
0
Influential Citations
11
Citations
Journal
Journal of Cell Science
Abstract
Autolytus Edwarsi St. Joseph at Plymouth lives upon Obelia. It deprives the hydroid of the hydranths and eats them. The worm cuts off the tentacles from the hydranth with the toothed crown of the chitinous tube (the ‘trepan’), and sucks them up through the protruded pharynx by establishing in the front part of the alimental tract by the activity of the proventriculus a continuous water-column which is drawn back into the intestine. The pulsation or pumping action of the proventriculus is particularly strong and distinctly visible at the outset of feeding. After a short time it dies away and the action is followed by peristalsis in the intestine. The entire organization in the front part of the alimental tract, which is the feeding apparatus of the Autolytus, suggests the system of a suction pump, the pharynx representing the pipe, the proventriculus the pump itself with a valve at each entrance, and the ventriculus the regulator of the water-column. The proventricular activity is due to the strong muscular development in the radial columns, which are stretched from the centre of the organ to the periphery. In each fibre are four contractile zones, three internodes, and two insertion parts. The contractile zones only are stainable with iron haematoxylin, and these may be comparable to the anisotropic bands of the striated fibre of the Arthropods and Vertebrates. In the middle of the internode there is a thickening, the internodular-nodule: the problem whether this point can be referred to the intrafibrillar part of the inophragm (telophragm in this case) is reserved for future discussion.