170 MARVELS OF POND-LIFE. 



liaving been thoroughly dried., may be heated without 

 loss of its sohibility; although if the same temper- 

 ature 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. Car- 

 penter 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 w^ork together for a common object; and as 

 might be expected from this fact, and also from 

 the repetition of distinct, although not articulated 

 limbs, they are provided w^ith 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 con- 

 sider the Tardigrada to belong to the great family 

 of Spiders^ of which they are, physiologically 

 speaking, jyoor relations. Like the spiders they 

 cast their skin ; and, although I was not fortunate 

 enough to w^itness 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 shew^ed that tlie stripping process extended to 

 the tips of the claws. The "Micrographic Diction- 

 ary" states that the Tardigrada lay but few eggs 



