940 THE AMERICAN NATURALIST. [Vou. XXXIII. 
lar in form and action to the original, though of course only 
about half the size. The time at my disposal was insufficient 
to observe whether there was subsequent growth of the speci- 
mens. In the recovery of the specimens I was not able, more- 
over, to observe any disposition to regenerate the additional 
radial canals necessary to complete the symmetry of the origi- 
nal. This, however, does not seem to be an important matter, 
since there does not seem to be a special necessity for a definite 
number.” , 
Hargitt also cut the medusa in two in a horizontal plane — 
one piece being bell-shaped and the other a ring. The former 
showed evidence in one case of forming new tentacles; the 
latter produced a new medusa. Referring to the latter, Har- 
gitt states that “ the process appeared as more a restoration 
of form” than the formation of a typical medusa. Neither 
mouth nor gastric cavity developed. The figure given to illus- 
trate this shows a small medusa with only fourteen tentacles 
around the margin, while the original piece contained thirty- 
eight tentacles. The absence of twenty-four tentacles is not 
accounted for, and is a point of some theoretical interest, since 
one of the important problems in connection with the devel- 
opment of a small medusa out of the ring is whether the old 
organs are retained intact or changed over into new ones pro- 
portionate in number and size to the smaller dimensions of the 
new individual. Hargitt also showed that if the manubrium is 
excised close to the stomach it is regenerated (2.2., a new one 
develops). 
These interesting experiments of Hargitt, although lacking 
in some details, show clearly that pieces of the medusa as small 
as one-fourth the whole have a remarkable recuperative power, 
leading to the production of the bell-like form, The account 
leaves the question open, whether these bell-like individuals 
will produce the missing organs if kept for a longer time. My 
object in studying the process of regeneration in this jellyfish 
was to find out more definitely by what means it regained its 
medusa form; whether by the development of new tissues and 
new organs, or whether by a rearrangement of the old part. 
Further, to find out if, after some time, the organs of a typical 
