R. R. Bensley 135 
Even if we admit that the cardiac glands occur in all mammals, it 
does not by any means follow that they have any palingenetic signifi- 
cance. 
If we reject the hypothesis of Oppel that the cardiac glands of mam- 
mals correspond morphologically to the simple fundus gland of the 
lower vertebrate classes, the possibilities as to the origin of these pecu- 
liar structures become reduced to the following: 
1. They are cwsophageal glands and the region which they Gr cuny 
is a portion of the esophagus; 
2. They are modified fundus glands; 
3. They are secondary structures of physiological importance which 
have arisen in the Mammalia in response to a new functional demand. 
The first of these hypotheses involves the discussion of the whole 
question of the participation of the cesophagus in forming the stomach 
of mammals. It is a well-known fact that in many mammals belonging 
to different sub-classes and orders, a considerable portion of the stomach 
is devoid of glands and provided with a stratified epithehum. This is 
more particularly the case in the Ungulata and Rodentia, but these 
cesophageal cardiac sacs also occur in the Cetacea, Edentata and Mar- 
supialia and in a few individuals belonging to other orders. The nat- 
ural conclusion based on the absence of glands and on the character 
of the epithelium would be that these sacs are produced by a dilatation 
of the lower end of the cesophagus, and this is the view taken by Ellen- 
berger and Edelmann, and more recently by Kingsley, 99. The latter 
author in his recent work on Vertebrate Zodlogy expresses his concep- 
tion of the morphology of these structures as follows: 
“Usually the stomach is regarded as the saccular enlargement of the 
alimentary canal, lying between the csophagus and the intestine; but 
when histological and physiological features are taken into account, it 
is seen that frequently the lower end of the wsophagus expands and 
takes part in the formation of the gastric enlargement, and that the 
stomach proper begins only where the gastric glands appear.” ‘This 
simple hypothesis is not, however, in accord with the results of com- 
parative anatomy and ontogeny, both the older anatomists, as for ex- 
ample, Gegenbaur and Wiedersheim, and the later investigators, Toep- 
fer, Fleischmann, Boas, Cordier and Oppel, agreeing to regard the stom- 
ach of mammals as a morphological unit of equal value throughout the 
group, the cardiac sacs having been produced by gradual modification 
of the condition found in a simple stomach, such as that of the Carni- 
vora and Insectivora and many individuals of other orders. 
Cordier, 90, whose important researches on the comparative anatomy 
