E. W. BERGER ON THE CUBOMEDUSA. il%( 
Stimulation.—Romanes found when he stimulated a deganglionated 
bell of a Hydromedusa, that it responded by a single contraction, 
while that of a Scyphomedusa responded with several quite rhythmic 
contractions. Charybdea in this respect agrees with the Scyphome- 
dusz. Romanes’ results were also verified on Aurelia. (Experiments 
12¢, 15, 50, 51.) 
Activity of Charybdea.—In speaking of the activity of Charybdea, 
I cannot do better than refer the reader to the notes. (Experiment 
41.) Conant remarks in his dissertation what an active swimmer 
Charybdea is, and this is further borne out by his later observations. 
Temperature.—Ice in the water seemed~to have no effect, except 
when held against an animal, when a slowing of pulsation followed 
in a few instances. On some pulsating actively in the sun the 
temperature of the water was found to be 92° F. (Experiments 33-35.) 
Conant does not’ tell us how cold the water became when he 
placed ice in it, but judging from his results, it seems that he might 
have obtained a decided slowing of pulsation if the water in which 
the medusze swam had been permitted to approach anywhere near 
the freezing point, say 35-40° F. Romanes obtained decided slowing 
of pulsation, and even complete inhibition, on a bell of Aurelia, as 
also a lengthening of the latent period on some strips cut from a 
bell of Aurelia, by lowering the temperature of the water. Replacing 
Aurelia in warmer water had the effect of immediate recovery and 
increased rhythm. In Aurelia, raising the temperature increased the 
rhythm but diminished it when the temperature of the water became 
70-80° F. After a slowing of pulsation due to such a rise of temper- 
ature, it would not quicken again when the animal was placed in 
water of its normal temperature. Romanes explains this by supposing 
that the tissue of the medusa had been permanently injured by the 
abnormally high temperature. It would be interesting to observe 
how the tropical Aurelia behaved under such treatment, seeing that 
Charybdea pulsated actively and without apparent injury in water at 
92° F. Limnocodium, noted by Romanes, and probably a tropical 
species, lived happily in water at 85° F. in the lily house of the Royal 
Botanical Society. The temperature of the water could be raised to 
100° F. before it proved fatal to this medusa. Such facts point to a 
decided difference in the constitution of the protoplasm of tropical and 
2 
