Emil Goetsch. 
co 
ve) 
mucous glands are present, indicating that, although the glands have 
been developed primarily for another purpose, their secretion never- 
theless serves the purpose of lubrication where it is present, and in 
so doing modifies the degree of specialization of the epithelium and 
muscularis mucose. For example in the pig, in the upper end of 
the esophagus where glands are abundant, no muscularis mucose 
is to be found, while in the lower end where few glands are present, 
it is highly developed. 
It will be noted that with regard to the processes of connective tis- 
sue which project into the epithelium and which are usually described 
as papille of the lamina propria mucose the observations here 
recorded confirm in general the conclusions of Strahl (89), who 
found that in many cases they were not true papille but elongated 
ridges of the lamina propria running in a direction parallel to the 
long axis of the cesophagus and connected with one another by oblique 
ridges. This is a matter in which it is very easy to be mistaken 
because ridges cut across are very similar in appearance to papillee. 
It is only by examining earefully series of sections, or whole prepara- 
tions of the epithelium, that this mistake can be avoided. Among 
the mammals examined true papille were found in the pig, ox, horse, 
sheep, and man and were associated in all these cases with longi- 
tudinal ridges of the lamina propria. In Didelphys, Arctomys, 
Sciurus, Tamias, Lepus, Canis, ridges only were present, although 
in Cavia and Tamias the irregular summits of the ridges afford 
suggestion of beginning papillae. In Procyon there are longitudinal 
ridges also with suggestions of low papillze on their summits, while 
in Mus, Geomys and Erethizon, there are neither ridges nor papille, 
but an epithelium of fairly uniform thickness. In Mephitis, finally, 
we have represented the exact opposite of connective tissue papille, 
inasmuch as the epithelium sends processes into the subjacent con- 
nective tissue. This is of course to be derived from a further devel- 
opment of the system of longitudinal and transverse ridges which 
have become so numerous and close that they surround papilla-like 
processes from the deep surface of the epithelium. 
With regard to the phylogeny of the cesophageal glands, the fact 
that in whole orders no glands are to be found and that each of the 
