Observations on some interesting phenomena in animal physiology, exhibited by several species of Planariæ / by John Graham Dalyell.

Date:
1814
Catalogue details

Licence: Public Domain Mark

Credit: Observations on some interesting phenomena in animal physiology, exhibited by several species of Planariæ / by John Graham Dalyell. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    the sphere of the solar rays ; all the won- derful operations of the bee are conducted in the dark. Most planarise court the light indeed ; but the flexilis rather inclines to shun it, less, we may conjecture, from being warned of its presence by the specks or eyes, than from some disagreeable sen- sation produced on the body. Apparently, the vicinity of food is recognized more from an analogous impression, whatever sense may be affected, than from vision. The body is surrounded by a smooth narrow margin, paler in colour than the rest, and of a different texture, participating, in a minor degree, of the gelatinous consistence which composes the general substance of the whole genus. From these character- istics, the species can hardly be mistaken, particularly as there is no other animal known to us that resembles it. The size of each individual is materially affected by the external temperature, and the food absorbed. As the day is warmer, the planaria is larger, and it sensibly dk
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