My specimens had no visible eyes, and these organs are, according to Pritchard's book, "variable and fugacious." The same authority remarks, "In most vital phenomena they very closely accord with the rotatoria; thus like these they can be revived after being put into hot water at 113° to 118°, but are destroyed by immersion in boiling water. They may be gradually heated to 216°, 252°, and even 261°. It is also by their capability of resuscitation after being dried that they are able to sustain their vitality in such localities as the roofs of houses, where at one time they are subjected to great heat and excessive drought, and at another are immersed in water." When vital processes are not stopped by excess of temperature, as is the case with the higher animals, the power of resisting heat without destruction depends upon the condition of the albumen. Soluble albumen, or, as it should be called, _Albuminate of Soda_ (for a small quantity of that alkali is present and chemically united with it), after having been _thoroughly dried_, may be heated without loss of its solubility; although if the same temperature was applied before it was dry, that solubility would be destroyed, and it would no longer be a fit constituent of a living creature. As Dr. Carpenter observes, this fact is of much interest in explaining the tenacity of life in the Tardigrada. The movements of the water-bears, although slow, evince a decided purpose and ability to make all parts work together for one common object; and as might be expected from this fact, and also from the repetition of distinct, although not articulated limbs, they are provided with a nervous apparatus of considerable development, in the shape of a chain of a ganglia and a brain, with connecting filaments. From these and other circumstances naturalists consider the Tardigrada to belong to the great family of _Spiders_, of which they are, physiologically speaking, _poor relations_. Siebold says "they form the transition from the Arachnoidæ to the Annelides."[26] Like the spiders they cast their skin; and, although I was not fortunate enough to witness this operation--called in the language of the learned _ecdysis_, which means putting its clothes off--I found an empty hide, which, making allowance for the comparative size of the creatures, looked tough and strong as that of a rhinoceros, and showed that the stripping process extended to the tips of the claws. The 'Micrographic Dictionary' states that the Tardigrada lay but few eggs at a time, and these are "usually deposited during the ecdysis, the exuviæ serving as a protection to them during the process of hatching." Thus Mrs. Water-Bear makes a nursery out of her old skin, a device as ingenious as unexpected. The water-bears are said to be hermaphrodites, but this is improbable. [26] 'Anatomy of the Invertebrata,' Burnett's trans., p. 364.