344 
POPULAR SCIENCE REVIEW. 
Most microscopists have at some time made acquaintance with 
the water-bears of our ponds, and a good many have followed 
their development. Whoever has done the latter has fully 
convinced himself of the truth of the statements of Kolliker, 
Frey, Doyere, Kaufmann and others, that the tardigrades in 
every instance produce large fecundated eggs, from which 
young, closely resembling the parents, emerge. Another 
feature of the tardigrades is the extreme hardness and toughness 
of their “ skin.” It is in point of fact, speaking relatively to 
the Arthoropoda, almost a “ shell.” This skin it is also well 
known is “ cast ” by the creature, and it forms, in the case of 
the female, a shelter or protection for her eggs. 
Now Dr. Bastian tells us that the power of reproduction in 
these forms is not limited to the 66 rudimentary generative 
organ,” because “ Dr. Grros tells us that the dead tardigrades 
may ultimately be resolved into specimens of Actinophrys, 
Peranemata, or Arcellinge,” and that these products may at 
different times be either all of one kind, or intermixed with each 
other and with young tardigrades ! On the strength of this 
discovery we are presented with a drawing which I reproduce, 
fig. 8. The subscription which accompanies this is very sug- 
gestive. It runs thus, viz. : “ Seven large germs into which the 
total internal substance of the 'parent has become resolved , 
each of them being capable of developing into a tardigrade .” 
Now, wherever there are plenty of tardigrades there will 
be found dead forms, with their internal structure unchanged, 
and others which are mere empty shells or skins. Some of 
these latter are, doubtless, “ cast skins ; ” but the dead water- 
bears, in a trough not very plentifully supplied with food, will 
soon be attacked by paramecia ; and although the aperture 
they make may not be clearly seen, they somehow get into the 
body of the animals, and gradually devour all that is in it ; and 
after cleaning it as thoroughly as ants will a small skeleton, 
leave it a hollow but perfect form. It is now open to the 
chapter of accidents, and it can be no matter for surprise that 
the minute eggs of aquatic creatures enter it and hatch there. 
This may be easily illustrated. Mr. Gr. F. Chantrell, the Secre- 
tary of the Microscopical Society of Liverpool, is a very careful 
and constant observer of pond-life. He has endeavoured to 
verify or substantiate some of the more marked cases presented 
by Dr. Bastian. But his method of examination is, of neces- 
sity, an interrupted one. He has frequently called my atten- 
tion to curious cases of apparent “ transmutation ; ” and I have 
before me now some of his drawings of these, taken from 
nature. In fig. 9 I reproduce one, which it will be seen is 
extremely like the one figured by Bastian (fig. 8), which, it 
must be remembered, he affirms, on the assurance of Grros, was 
