Slime Secretion Research Articles

Morphological Notes on the Terrestrial Triclad Rhynchodemus britannicus Percival.

Summary. The occurrence in Sheffield of the terrestrial planarian Rhynchodemus britannicus is recorded. Variations in the genital system, in addition to those already recorded, are described, and it is suggested that these are stages in the attainment of sexual maturity. A sphincter on the female vestibular apparatus formed by longitudinal muscles arranged spirally is described. The previously recorded secretion of calcareous slime is attributed to gland cells in the ectoderm and subectodermal parenchyma.

FORM-REGULATION IN CERIANTHUS, III

1. The inrolling of the margins and the closure of openings by contact of the inrolled margins is the result of the elasticity of the body-wall. This elasticity must be greater in the inner portions than in the outer portions, in order to produce the results observed. The facts indicate that the mesoglœa plays the most important part in this elastic contraction.2. Openings between folds of the inrolled body-wall may be stopped by the ectodermal slime secretion. This method of closure often occurs in pieces before the formation of new tissue and permits the existence of considerable water-pressure in the enteron.3. Contact or close approximation between two cut surfaces or parts of a cut surface is a necessary condition of the growth of new tissue from these surfaces. A single exposed cut surface may heal over but no further growth occurs from it.4. The new tissue having arisen at a point of contact between two cut surfaces is capable of extending in the form of a thin membrane for a certain distance between diverging cut surfaces ; the distance to which it extends is determined in a given species by the angle of divergence of the cut surfaces, and in different species by the thickness and quality of the membrane.5. The new tissue rising between two cut surfaces behaves in certain respects as if subject to the laws of capillarity.