516 Edwin G. Kirk. 
anatomy and histology. It has been pointed out that general, 
mucous differentiation occurs slightly earlier in the cardia than 
in the fundus, although it is less uniform. The cardiac glands, in 
their whole development, display a very decided mucous char- 
acter, as manifested in the discarding of the deep, zymogenic 
segment of the fundic tubule, in the involution of parietal cell, 
and in the slight acceleration of the mucous differentiation. This 
must be a response to a functional demand. Bensley has already 
suggested (02 p. 147) that in these retrogressive glands, the 
cellular types disappear in the order of their specialization,— 
zymogenics first, parietals next. We find that not only is there 
no tendency on the part of the mucous cells to disappear, but 
that they even differentiate at a. slightly earlier stage. Probably 
the altered food, or the other conditions which have brought 
about the involution of fundie to cardiac glands, have also de- 
manded an increased mucus secretion. 
It will be recalled that, while part of the caecal glands were 
as retarded as those of the cardia proper, others kept pace with 
the pyloric tubules, both types, however, developing parietals. 
Later, all the caecal glands, whether precocious or retarded, 
shared the fate of the cardiac tubules. This would seem to in- 
dicate that seclusion in the secondary pouch has tended to parti- 
ally protect these galnds from the regressive changes which have 
attacked the old left fundic area. 
Bensley’s comparative work on the mammalian stomach (Op. 
cit. ’02) led him to the same conclusion, 
b. Cell specificity 
( 
At 2 cm. all the cells are of the type described as ‘‘embryonic 
gland cells.” From 3 em. on, some of these are constantly dif- 
ferentiating into parietals, others retaining their undifferentiated 
character for a shorter or longer period. Both types multiply 
mitotically. 
From 6 em. on, certain of the adelomorphs differentiate into 
mucous cells, both mucous chief and goblet. New parietals and 
new mucous cells arise, differentiating from adelomorphs. The 
