No.3. | TAMOLUS POLVYPHEMTS. 433 
oesophageal ganglion) does not influence the respiratory mech- 
anism of Limulus. For if we cut either transversely or 
longitudinally into the brain (4 Fig. 1),—or, if we injure 
or extirpate half, more or less than half, or even the entire 
brain, we find that when the effects of the operation have 
passed off, the respiratory movements still remain normal. 
B. Experiments on the Oesophageal Collar. 
Of the results of the experiments on the oesophageal collar, 
it need only be said, that they had no influence on the respir- 
atory movements. If we cut between the ganglia of either 
side of the collar, extirpate one or more of the ganglia (7 
Fig. 1) or remove the entire collar (C Fig. 1), the respiratory 
activity still continues, 
C. Experiments on the Post (sub) Oesophageal Ganglion. 
The results of Faivre’s experiments led me to think, that 
the post-oesophageal ganglion might influence the respiratory 
activity of Limulus. If, however, we injure or extirpate part 
or the whole of the ganglion (G Fig. 1), we find that the 
respiratory movements still persist in their normal activity. 
For several days after the operation, the gill-plates may 
remain, sometimes for hours, in the expiratory phase, while the 
animal remains perfectly quiet. But after a while the respir- 
atory activity spontaneously begins again, and continues for 
days and even months. The interrupted respiratory movement 
is not a matter of consequence, since, as was said, it often 
occurs in normal Limuli. 
D. Experiments Anterior to the Abdominal Cora. 
Perhaps the most difficult and interesting operations were 
those, in which the whole brain, with the oesophageal collar 
and post-oesophageal ganglion were extirpated, thus leaving 
only the abdominal cord (PD Fig. 1), which now had an oppor- 
tunity to prove its function, unaided by any other part of the 
central nervous system. 
