356 ADOLPH R. RINGOEN 
On comparing figures 2 and 3 (the latter an embryo of 137 
mm.), it is apparent that gland rudiments are now sharply 
marked off from the neighboring epithelial cells. In embryos 
of 137mm. in length, such areas are very numerous. The 
entire epithelium of the stomach is literally studded at regular 
intervals with them. At this time none of the cells making 
up a gland rudiment present staining characters bordering on 
those of the epithelial cells. The nuclei present about the same 
staining reactions as portrayed in figure 2. There has been, 
however, a considerable progressive change in their shape. 
Figure 3 shows two gland rudiments embedded in the epi- 
thelium. They present such a striking appearance in sections 
of the stomach (137-mm. specimens) that one cannot fail .to 
notice them. The regularity in their distribution is indeed 
striking. Never have I seen similar rudiments lying at the 
base of the epithelium. Obviously, there would be no reason 
for such a location, since the early gland rudiments are simply 
transformed epithelial cells. In the same figure the two gland 
cells at the extreme right represent only a portion of a gland 
rudiment, due to the plane of sectioning. 
That the potentialities of the epithelial cells are by no means 
the same is particularly evident in the gastric epithelium of 
Acanthias specimens 137 mm. in length. Every gland of the 
adult specimen is represented at this stage by its own epithelial 
modification or gland rudiment. 
C. Influence of the gland rudiments on the epithelium 
The differentiation and presence of the gland rudiments in 
the epithelium has had a profound influence on the final con- 
figuration of the epithelium itself. During the early stages of 
differentiation it increases in thickness; at no time is it strat- 
ified, although in the early stages of embryonic development 
the disposition of the nuclei in several planes simulates strat- 
ification. In Acanthias embryos 133 mm. in length, the epi- 
thelium consists of columnar cells with their lateral surfaces 
closely approximated (fig. 2). The differentiation and pres- 
