Marcu 22, 1912] 
idly than if starved in sea-water which has been 
passed through filter paper but not heated. This 
leads one to suspect that Piitter’s ‘‘dissolved 
food’’ in sea-water may not be available unless 
some bacteria or other organisms be present in the 
sea-water to stimulate or maintain a synthesis of 
the inorganic ingredients of sea-water that may 
result in building up the animal body. In other 
words, sea-water as such may not be a nutrient 
fluid for animals unless acted upon by certain plant- 
like organisms in the immediate presence of the 
animal itself. As a side issue of this research, it ap- 
pears that the so-called ‘‘ converse relation between 
ciliary and muscular movements’’ in ctenophores, 
trochophores, veliger larve, etc., is not a chemical 
but merely a mechanical matter. When the 
muscles contract pressure is brought to bear upon 
the ciliated cells, and this renders them relatively 
insensitive to stimuli and the cilia stop; vice versa 
when the muscles relax, as under the influence of 
magnesium, the normal stretching of the cilia- 
bearing epithelium is reduced and the cilia are 
free to beat incessantly, as do isolated cilia-bearing 
cells when mechanically torn away from the epi- 
thelium and set free in the water. 
This paper may appear in the forthcoming 
volumes of ‘‘Researches from the Tortugas Labo- 
ratory of the Carnegie Institution of Wash- 
ington.’’ 
The Temperature Reactions of Meduse Ranging 
from Temperate to Tropical Oceans: ALFRED G. 
Mayer, the Carnegie Institution of Washington. 
In species of Aurellia, Limulus and Pennaria 
which range from cold to warm seas, it is found 
that individuals living in the tropics have a higher 
optimum and a higher death temperature than 
have those living in cold seas. Also the individuals 
in the tropics can not withstand such low tem- 
peratures as do individuals of the same species in 
cold seas. For example, consider the case of 
Aurellia aurita, the common scyphomedusa, which 
ranges from pole to pole and is found in all 
oceans: Aurellia aurita from Tortugas, Florida, 
is killed if frozen into the ice, but specimens from 
Halifax, Nova Scotia, survive this treatment. 
A strictly tropical medusa, such as Cassiopea 
frondosa is killed at from 8°.2 to 9°.7 C., but it 
continues to pulsate up to about 38°.3-40° C. 
Evidently it could not survive in cold seas, and 
this may account for the fact that not a single 
species of Cassiopea has ever been found in the 
temperate regions. On the other hand, a form 
confined to arctic or cold seas, such as Cyanea 
SCIENCE 
465 
arctica from Halifax, Nova Scotia, pulsates until 
frozen into the ice, a treatment which causes it no 
apparent injury. On the other hand it is killed 
by 30° C. Thus it could not survive in the surface 
waters of the tropics and no Cyanea has yet been 
found in tropical waters. On the other hand the 
case of Limulus shows us that temperature resist- 
ance is by no means a sole factor in determining 
the geographical range of animals, for on the 
Massachusetts coast Limulus remains active from 
—1°.1 to 41° C. and at the Marquesas Keys in 
Florida from 0.8° to 45°.7 C. Yet it ranges only 
from Maine to Yucatan, and all attempts to intro- 
duce it upon the coast of Europe have failed. 
This paper may appear in the forthcoming 
volume 5 of ‘‘ Researches from the Tortugas Labo- 
ratory of the Carnegie Institution of Wash- 
ington.’’ 
Symmetry in Regeneration: HErBpert W. RAND, 
Harvard University. 
When a bilaterally symmetrical metazoan is 
bisected in a plane oblique to its long axis, regen- 
eration, if it occurs, takes place in such manner 
that asymmetry, in the ordinary geometrical sense 
of that word, persists until regeneration is nearly 
or quite completed. The literature dealing with 
such experiments contains many descriptions which 
indicate or suggest that the new part, in the 
earlier stages of its regeneration, lacks, as regards 
form and organization, coordination with the old 
part; and that coordination of new and old parts 
to constitute a normal whole is secondarily ef- 
fected by means of organogenetie and regulatory 
processes. 
These descriptions give rise to misconcep- 
tions regarding the true nature of the regenera- 
tive process. A reinvestigation of regeneration 
from oblique surfaces in planarians reveals evi- 
dence that the new material is, from the very 
beginning of the regenerative process, in the 
highest degree coordinated with the old. While, 
during regeneration, the total material is asym- 
metrical in a geometrical sense, nevertheless a per- 
fect organic symmetry exists in the sense that 
such materials and energies as are present are 
distributed upon either side of a morphological 
median surface (not a plane surface) with precise 
regard to a certain completeness of plan which 
remains to be worked out only in a quantitative 
way. This unity of organization certainly exists 
from the moment when the formation of new tissue 
begins—perhaps even before regeneration is out- 
wardly manifested. 
