|Description:||This 2005 scanning electron micrograph (SEM) depicted the morphologic characteristics of the inner surface of an unidentified bird’s eggshell. In this view the details revealed included the surfaces of the mammillary cones, some of which are hollowed-out leaving behind what are known as “mammillary voids”, and a number of intermammillary pores, i.e., canals that span the distance between the shell’s outer cuticle layer, and the interior membranous layers. It is through these pores that the diffusion of gasses takes place. It has been found that the distribution of these pores is directly related to the strength and durability, and the respiratory efficiency of the shell structure on a regional basis. This shell fragment was retrieved from the grounds of the Decatur, Georgia suburbs; Magnified 307x.|
The presence of the voids indicates that this shell was a fragment from a fertile egg. The voids are created when eggshell calcium content is leeched away from the shell structure, and deposited into the developing embryo during the incubation process. The shell is created when calcium carbonate is embedded in an organic matrix.
The lamellated eggshell acts as the developing embryo’s respiratory system to the outside world, regulating the exchange of gasses such as carbon dioxide and oxygen, as well as water vapor through its strategically structured porous architecture.
The inner membranes are easily pulled free from the shell’s interior surface in the case of a fertile, incubated egg, due to the reduction in calcium from the shell during embryonic development, reducing the structural integrity between the membranes and the shell proper. This is likely the case here, evidenced by the missing membranous layers.