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On the Stomach of the Narwhal (Monodon monoceros)

Published online by Cambridge University Press:  15 September 2014

Robert W. Gray
Affiliation:
Student of Anatomy, the University, Edinburgh
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Extract

Although numerous most admirable descriptions of the stomach of various species of Delphinidae (the family of toothed Whales to which the Narwhal belongs) have from time to time appeared from the pens of most able observers (of whom a list will be found in the references appended), we have found it impossible to find anything more than a mere indication of the histological structure of the various portions of the walls of the peculiar digestive apparatus of these animals. As one of us had an opportunity of obtaining material in a comparatively fresh condition, we decided to make arrangements for preserving it properly, so that it might be subjected to microscopic examination on being brought to this country, With all the care that was taken some portions of the mucous membrane have suffered slightly, but in all cases the changes are so slight that we are enabled to speak positively on the points to which reference is made.

Type
Proceedings 1888-89
Copyright
Copyright © Royal Society of Edinburgh 1889

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References

note * page 793 Since this was read, we have seen Professor Max Weber's admirable paper, in which a description of the histological structure of the stomach is given, Morph. Jahr., 1887–1888, p. 637 et seq.; and Sir Win. Turner's paper on “Additional Observations on the Stomach in the Ziphioid and Delphinoid Whales,” Jour. Anat. and Phys., vol. xxiii. p. 466 et seq.

note † page 793 The stomach obtained was that of an adult female, 14 feet in length, killed in the Greenland Sea during the summer of 1888.

note * page 796 It is just possible that this may have to be looked upon as the direct continuation of the oesophagus, as we find that the longitudinal muscles converge in a most peculiar manner at the apex where the wall is exceedingly thin, and there is formed a small stellate mass of fibrous tissue at this point, into which the particular fibres are inserted as it were.

note * page 798 In the Greenland whale, Belœna mysticetus, near the extremity of the upper jaw, a blindly-ending depression is found on each side of the middle line within the cavity of the mouth, which, as Eschricht and Keinhardt suggest (“Recent Memoirs on the Cetacea,” Memoirs of the Ray Society), probably represent the rudiments of Stenson's duct.

note * page 800 (5) Page 247.

note † page 800 (6) Page 247.

note * page 802 Trans. Zool. Soc. Land., vol. viii. part 4, p. 257.

note † page 802 “Anatomy of Sowerby's Whale,” Jour. Anat. and Phys., October 1885, p. 154.Google Scholar

note * page 805 Turner, loc. cit., would speak of the cardiac cavity as that immediately following the cesopbageal paunch; then there would be two intermediate cavities; and lastly, a simple pyloric cavity.

note * page 806 Since the above was read, Professor Sir Wm. Turner has published an iceount of the stomach of a full-time foetal Narwhal (Jour, of Anat. andPhys., vol. xxiii. p. 486, “On the Stomach of Ziphioid and Delphinoid Whales ”), in which he states that “the duodenum arose from the right and posterior aspects of the fifth compartment. It was somewhat dilated at its commencement, but soon became a cylindriform tube.…. The mucous lining of the dilated portion was smooth, that of the cylindriform tube was elevated into valvulæ conniventes. Close to where the cylindriform part of the duodenum began was a semilunar fold of mucous membrane, which bounded the orifice of the hepatico-pancreatic duct.”