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Quarterly Journal of Microscopical Science, Vol s2-73, 243-274, Copyright © 1929 by Company of Biologists

Memoirs: The Histology of the Alimentary Tract of the Plaice (Pleuronectes Platessa)

BEN DAWES A.R.C.S., D.I.C.1

1 Research Assistant to the Marine Biological Association at Plymouth

1. Structures similar in detail to the taste-buds of mammals occur in the epithelium of the pharynx, which is considered as a distinct region for reasons given.

2. The oesophagus possesses an extremely well-developed musculature composed of striated fibres and an intensely folded mucosa liberally beset with goblet-cells. There are no glands present, and it is sharply denned from the stomach.

3. The musculature of the stomach consists of non-striated fibres, and there is no differentiation between the gastric glands at the ‘cardiac’ and ‘pyloric’ ends of the stomach, except that in the former position they are more shallow.

4. Three types of cells enter into the composition of the gastric mucosa, superficial cells forming the surface epithelium and that lining the crypts, mucus-producing cells forming the neck of the tubule, and granular cells forming the basal, secretory portion of the tubule. Parietal or oxyntic cells do not occur, nor do goblet-cells, in any part of the gastric mucosa.

5. The intestinal mucosa is folded so as to simulate crypts and villi, but it is shown that these structures do not occur. There is no differentiation of the intestinal epithelium except into goblet-cells. Leucocytes are seen in all zones of the epithelium at all times but in relatively small numbers which appear constant, so that they probably do not play any considerable part in food absorption.

6. The pyloric caeca exhibit the same histological structure as the intestine and are in open communication with this part of the alimentary tract. They are probably secretory and absorptive like the duodenum and intestine.

7. A well-developed valve occurs at the junction of the intestine and the rectum. The rectum shows the same structure as the intestine except that the folds are deeper and more considerably beset with goblet-cells and the musculature thicker. Goblet-cells disappear from the mucosa near the anus.






© The Company of Biologists Ltd 1929