At this point there is a halt. The medusa
remains in its polype state for some months. At the expiration of this
term, a strange alteration in its appearance begins to take place.
Rings are formed round its body, from ten to fifteen in number. These
gradually deepen, until at length it is literally cut up into a number
of segments, which rest one upon the other--their upper margins
becoming elevated, and divided into eight lobes. It is, in fact, a
pile of cup-shaped pieces, very loosely connected together. A little
later, these pieces free themselves successively, and the sedate
polype disappears in a company of sprightly young medusae. These
beings, indeed, still differ in some respects from the adult animal;
but the differences gradually vanish, and we have the perfect
jelly-fish as the final result of this extraordinary series of
transformations.
Similar observations have been made respecting other tribes amongst
the lower animals, and some interesting generalisations have been
founded upon them, into which, however, it is not our present purpose
to enter.
Pages:
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66