Chapter 50.2, Problem 1SB

Summary Introduction

To review:

The role of the gray crescent in amphibian development.

Introduction:

The amphibian egg is divided into two halves: animal half and vegetal half. The yolk remains concentrated in the vegetal half. The animal half is darkly stained due to the presence of a layer of pigment granules just below the surface. The sperm strikes the egg in the animal half and then the pigmented layer of cytoplasm rotates toward the site of the sperm entry, forming a crescent-shaped region. This region is just opposite to the site of sperm entry and known as gray crescent.