Noes sl LIMULUS: POLYPHEMUS. 441 
(2) Nearly the same result is obtained in those Limuli that 
had part or whole of the brain, collar, or post-oesophageal 
ganglion removed (Fig. 1). 
(c) In one Limulus in which the entire brain, collar, and 
post-oesophageal ganglion were extirpated, a very interesting 
result was obtained. 
When the animal was in a dying condition, and the respira- 
tion had to all appearances ceased, it was found that they could 
be aroused again, and always for a certain period of time, by a 
slight stimulus on the plates or carapace. 
For example, when the plates were motionless, and the 
abdominal carapace was pinched with a certain pressure, after 
a definite interval the plates began their activity, at a certain 
rate and extent. This activity lasted just seventy-five seconds, 
fora given pressure. If after a few minutes the stimulus 
was repeated, we obtained about the same number of 
inspirations in the same time. If the pressure was in- 
creased, the rate and its duration was also. This relation of 
stimulus and duration of reflex action was maintained for 
two hours, when a greater stimulus was required to arouse 
activity. The movements then lasted only sixty seconds, and 
the interval between pressure and reaction was lengthened. 
After an hour the activity of the plates could no longer 
be aroused. 
(2) If, in a Limulus that had the cord cut from the post- 
oesophageal ganglion (D and G, Fig. 1), parts posterior to 
the lesion are touched, the gill-plates stand in expiratory phase 
for several seconds. But no sign of annoyance is evinced, 
either by the appendages beating about, or attempts made 
to turn over. If, however, parts anterior to the lesion are 
touched, so that the abdominal part does not turn ventrally, 
and thus have a secondary influence, the gill-plates are not 
disturbed in their rhythm. 
(ec) The following are some of the results on reflex action in 
Limuli, whose cord was cut between the second and third 
ganglion (II and III, Fig. 1). If parts posterior to the lesion 
are touched, the posterior division of plates stands in expiratory 
phase while the pressure lasts. 
