Marvels of Pond- Life. 133 



they are provided with a nervous apparatus of con- 

 siderable 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 Arachnoidae to the Annelides."* 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 ex- 

 tended to the tips of the claws. The f Micrographic 

 Dictionary ' states that the Tardigrada lay but few eggs 

 at a time, and these are " usually deposited during the 

 ecdysis, the exuvise 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. 



The Plumatella repens, described in a former chapter, 

 was kept in a glass trough, to which some fresh water 

 was added every few days, taken from a glass jar that had 

 been standing many weeks with growing anacharis in it. 

 One day a singular creature made its appearance in the 

 trough; when magnified sixty diameters it resembled 

 an oval bladder, with a sort of proboscis attached to it. 

 * ' Anatomy of the lnvertebrata/ Burnett's trans., p. 364. 



