The Structure of the Mammalian Csophagus. 7 
On the surface of the epithelium a well-defined stratum corneum 
is seen, of fairly uniform thickness, although it dips down some- 
what in the intervals between the longitudinal ridges of the lamina 
propria. This corneous layer presents two distinct strata, which 
correspond in a general way in their appearance and staining reac- 
tions to the stratum lucidum and stratum corneum of the epidermis. 
The deeper layer, 85 micra in thickness, stains deeply in eosin, par- 
ticularly at the deep and superficial margins, the intermediate por- 
Stratum corneum 
Stratum lucidum 
: Stratum 
e  germinativum 
— Lamina propria 
Zt -mucose 
Fic. 1. Transverse section of epithelium of cesophagus of Didelphys at 
level of cricoid cartilage. 120. 
tion exhibiting, as is often the case with the stratum lucidum, patchy 
or irregular staining. ‘This layer is composed of flattened cells, 
elongated, spindle-shaped in section, with a flattened nucleus rod- 
shaped in section. ‘The superficial layer, 17 micra in thickness at 
its thickest portion, stains but faintly in eosin. It consists of cells 
of irregular polygonal shape similar to those of the stratum corneum 
of the epidermis with the exception that remains of the nucleus are 
to be found in them, in the form of shrunken remains of the nuclear 
membrane and one or two chromatic particles. 
