CO-ORDINATION. 143 
Number of ~ 
contractions Am ber | N mes 
: during five HS Peay ane ive Ultimate 
Name of species. = minute minutes 
ees : after afeae effects. 
ore opera- ; ; 
tian: operation. | operation. 
Tiaropsis diademata 57 11 0 Permanent 
indicans _... 148 23 0 rest. 
polydiademata 102 18 0 . 
oligoplocama 131 39 0 ~ 
Sarsia tubulosa ... 144 56 14 ve 
This decided effect of so slight a mutilation will 
not, perhaps, appear to other physiologists so note- 
worthy as it appears to me; for no one who has 
not witnessed the experiments can form an 
adequate idea of the amount of mutilation of any 
parts, other than their margins, which the Medusze 
will endure without even suffering from the effects 
of shock. Another point worth mentioning with 
regard to the operation we are considering is, that 
not unfrequently the interruptions of the margin, 
which have been produced artificially, begin to 
extend themselves through the nectocalyx in a 
radial direction ; so that in some cases this organ 
becomes spontaneously segmented into four quad- 
rants, which remain connected only by the apical 
tissue of the bell. I do not think that this is due 
to the mere mechanical tearing of the tissues as 
a consequence of the swimming motions, for the 
latter seem too feeble to admit of their producing 
such an effect. 
In conclusion, I may state that I have been able 
temporarily to destroy the ganglionic co-ordination 
