118 PROP. W. B. BENHAM ON THE [May 21, 



into the stomach as an irregular fringe, or, as Huxley describes it 

 in the Porpoise, as a " prominent rugose lip." 



The communication between oesophagus and paunch is by M'ay 

 of a deep groove bounded by a couple of high and thick folds {d.cl) 

 on the outer wall of the oesophagus. It is similar to the groove 

 between the oesophagus and psalterium in the Cow's stomach. It 

 is evident that the paunch is a blind, downward prolongation 

 of the oesophagus, beyond the entrance of the latter to the 

 stomach. 



The passage from, the cardiac to the pyloric chamber is between 

 two stout curved folds of mucosa and submucosa, forming valves, 

 which only incompletely circumscribe the aperture. One valve, 

 the superior, is contiuuous with the surface of the cardiac 

 chamber, and its free edge is concave backwards ; the other, or 

 inferior valve, is at a slightly diiferent level, being the projection 

 forwards of the adherent wall of the pyloric chamber ; this fold 

 is concave forwards, and its right end overlaps that of the superior 

 valve. Eurther, as part probably of the apparatus, there is a 

 stroug rounded ridge (3 inches in length) in the ventral wall of 

 the pyloric chamber, passing forwards and curving over the 

 inferior valve. 



The mucous membrane of these parts exhibit very characteristic 

 differences, both macroscopic and microscopic ; these have been 

 described for some Cetacea by Sir W. Turner in some detail 



The lining of the oesophagus (PL IX. fig. 11), which in the 

 preserved specimen is whitish and hard to the touch, is thrown 

 into labyrinthine folds, the general trend of which is transverse. 



In sections, the epithelium is seen to be " stratified," consisting 

 of some 6 or 7 layers of cells : the nuclei of the deepest layer are 

 oval and closely set ; the upper ones are more or less flattened, and 

 those on the free surface quite flat. These last take the stain 

 (haematoxylin) much more faintly than the deeper ones. The 

 surface of the epithelium is very ill-defined and irregular, due 

 partly no doubt to the manipulation it had undergone ; though, 

 partly, this seems to be a natural character, for even in the deep 

 pits formed by the above-mentioned foldings, where the tissue 

 would be less liable to disturbance, the epithelium is comparatively 

 thin. Moreover, it is everywhere of very irregular depth, as the 

 subumucosa rises up into it at intervals in such a way that the 

 epithelium seems to dip downwai-ds in the form of solid columns ; 

 and I imagined that these were tangential sections of small pits ; but 

 I failed even in thin sections to determine the existence of any- 

 thing of the kind. I find that Sir W. Turner notices the same 

 thing in the Porpoise, and suggests that they are " in all probability 

 slender folds of the mucous membrane, which when vertically 

 divided look in sections as if separated by papillse " of the under- 

 lying connective tissue. 



There are no glands, either macroscopic or microscopic, in the 

 wall of the oesophagus. 



