The otic labyrinth and equilibration in one of the urodela (necturus maculatus s. menobranchus lateralis) / by G.N. Stewart.

  • George Neil Stewart
Date:
[Between 1912 and 1919?]
Catalogue details

Licence: Public Domain Mark

Credit: The otic labyrinth and equilibration in one of the urodela (necturus maculatus s. menobranchus lateralis) / by G.N. Stewart. Source: Wellcome Collection.

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    lying in the water with its lateral surface downwards it quickly brings its mouth to, its tail first on one side and then on the other, forming a circle when the mouth has reached. the tail. Mar. 18. It can no longer sink, but lies on the surface of the water, some- times on its back, sometimes on its left side. The vibratory movements (fig. 1) are exceedingly well marked, especially when it tries to reach the bottom. The gills are not moved much. Mar. 22. Died. The fungus noticed last year was present on the head and gills, and also a patch on the side. The necropsy Showed that both otic capsules had been destroyed. In one animal both otic capsules were destroyed at one operation (May 7, 1895). When placed in water im- mediately thereafter the gills moved constantly, as in an animal deprived of its cerebral hemispheres. When placed -on its back the animal showed little inclination to right itself. Next day it seemed restless. When stimulated it moved as if turning somersaults (fig. 4), but came to rest again always in the normal posi- ‘tion. When at rest there was no obvious difference between it and the contro! and the gill movements were now not conspicuous. Its behavior did not change much during the time it continued to live, except that on the last day stronger stimula- tion was necessary to elicit the move- ments. It died on the fifth day after the operation. The ,,somer- sault’”’ movements are far less com- mon than the lateral twisting movements already described, which were also seen in this animal. Bending movements in the horizontal plane, the back first becoming convex and then concave, as the animal lies on its side (fig. 5) were rarely observed. The twisting movements (fig. 1), as if it were attempting to catch its tail, first to one side and then to the other were seen in an animal in
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