Computed Profiles of Compressed Sea-Urchin Eggs with Elastic Membranes

Abstract

A computer simulation was made for profiles of compressed sea-urchin eggs with various amounts of elasticity at their surfaces. Fluidity of cytoplasm and negligible bending stress of the surface were assumed a priori. Based on the profiles thus calculated, the relation of the force of compression and the degree of flattening was predicted and matched with the observed force and flattening of unfertilized eggs of Hemicentrotus pulcherrimus. The experimental data were shown to fit well with the calculated force-deformation curve on the assumption of non-elasticity at the surface. The possibility that the egg surface had an elasticity modulus of 10^[3] dyne/cm2 was precluded.