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Nature of the sites inhabited Can live long under water Nocturnal Wander about at night Often lie close to the mouths of their burrows, and are thus destroyed in large numbers by birds Structure Do not possess eyes, but can distinguish between light and darkness Retreat rapidly when brightly illuminated, not by a reflex action Power of attention Sensitive to heat and cold Completely deaf Sensitive to vibrations and to touch Feeble power of smell Taste Mental qualities Nature of food Omnivorous Digestion Leaves before being swallowed, moistened with a fluid of the nature of the pancreatic secretion Extra-stomachal digestion Calciferous glands, structure of Calcareous concretions formed in the anterior pair of glands The calcareous matter primarily an excretion, but secondarily serves to neutralise the acids generated during the digestive process.
With respect to the function of the calciferous glands, it is probable that they primarily serve as organs of excretion, and secondarily as an aid to digestion. Worms consume many fallen leaves; and it is known that lime goes on accumulating in leaves until they drop off the parent-plant, instead of being re-absorbed into the stem or roots, like various other organic and inorganic substances.
Land must be chosen of middling grain; somewhat difficult, calciferous soil is particularly recommended, when it is richly fertilized with the remains of decayed plants, and not less than two feet deep; and the deeper the roots are inserted the higher will the plant grow.
Perhaps the nearest analogy may be found in such plants as Drosera and Dionaea; for here animal matter is digested and converted into peptone not within a stomach, but on the surfaces of the leaves. Calciferous Glands. But almost as many theories have been advanced on their use as there have been observers.
A great enlargement in one direction of several oval pipes would give rise to the lamellae. Besides the free calciferous cells in which no nucleus was visible, other and rather larger free cells were seen on three occasions; and these contained a distinct nucleus and nucleolus. They were only so far acted on by acetic acid that the nucleus was thus rendered more distinct.
The large quantity of carbonate of lime secreted by the calciferous glands apparently serves to neutralise the acids thus generated; for the digestive fluid of worms will not act unless it be alkaline. As the contents of the upper part of their intestines are acid, the acidity can hardly be due to the presence of uric acid.
Therefore it seems highly probable that the innumerable calciferous cells, which are poured from the four posterior glands into the alimentary canal of worms, serve to neutralise more or less completely the acids there generated by the half-decayed leaves.
The pharynx leads into the oesophagus, on each side of which in the lower part there are three pairs of large glands, which secrete a surprising amount of carbonate of lime. These calciferous glands are highly remarkable, for nothing like them is known in any other animal. Their use will be discussed when we treat of the digestive process.
There seems to be but little doubt, however, that part of the series is equivalent to the Calciferous of other regions. It is also pretty well determined that certain of the lower beds, all below the 'Saccharoidal' Sandstone perhaps, are representatives of the Upper Cambrian or Potsdam. These conclusions appear well grounded both upon stratigraphical and faunal evidence.
The ashes of a leaf of an acacia have been known to contain as much as 72 per cent. of lime. Worms therefore would be liable to become charged with this earth, unless there were some special means for its excretion; and the calciferous glands are well adapted for this purpose.
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