492 Edwin G. Kirk. 
from adelomorphs, larger and larger groups and rows appear in 
later stages. I do not believe that new ones develop from adelo- 
morphs after 13-14 em. and it seems almost certain that this does 
not occur after 19-20 em., as all the adelomorphs have at tnat time 
differentiated into other types, mucus or zymogenic. Thus, in 
the latest stages, the parietals probably arise only by division of 
parietal predecessors, unless there is a genetic relation between 
parietals and zymogenic or mucus cells, of which I found no 
evidences. 
If the section of the early gland be even slightly oblique the 
parietals, whether isolated or in small groups, appear as conspicu- 
ous, large, granular cells, lying apparently between the bases 
of the surrounding adelomorphs and often as if far removed from 
the surface. If cut obliquely, the cells appear of ovoid contour, 
if cut transversely, of circular outline, hence sometimes inter- 
preted as referable to a spherical shape (Ross, ’03). Figs. 4b, 5a, 
and 9a illustrate this condition, as do Ross’ (’08) figs. 25, 26, 
and 24. Byreconstruction it is found that they reach the surface. 
Vide figs. 4a representing the section adjacent to 4b, 5b adjacent 
to 5a; 9b where obliquely cut parietals are shown, including the 
distal end of one. These obliquely cut parietals are much more 
conspicuous objects than are the obliquely cut bases of the sur- 
rounding adelomorphs, owing to their larger size, granulation 
and deep red color. This probably accounts for the inconsistency 
of the interpretations of Ross, whose figures show the obliquely 
cut bases of parietal cells surrounded on all sides by undifferen- 
tiated cells, likewise cut obliquely. The parietal cell bases are 
then described as basal gland anlagen, which have never yet 
approached the surface of the epithelium; curiously, this inter- 
pretation is not extended to the obliquely cut bases of the adelo- 
morphs. Ross’ figs. 28 and 29 are especially significant as 
showing the true condition, and are in perfect accord with my 
findings. The little depressions mentioned by Toldt and Ross 
(Ross ’03, fig. 24d) and interpreted as surface insinkings which 
later communicate with the fundus of the gland, are shown in 
my fig. 4b etc., but a glance at adjacent sections (as 4a) always 
shows that they are merely part of the shallowlumenof the gland, 
