i as 
1884.] in the Legs of Certain Hemiptera. 17 
Observations on Amputated Legs—A strong proof that the pul- 
satile organs are separate from the general muscular system of 
the legs, is found in their automaticity. About twenty-five obser- 
vations have now been made with the amputated legs of Ranatra 
and Perthostoma to study this phenomenon. When an amputated 
leg is placed under observation, the pulsatile organ is seen in 
motion similar to its action during life. It has already been noted 
that the pulsations are somewhat intermittent in life, and this 
characteristic is usually aggravated after amputation, so that the 
stops are more frequent and longer continued than before ampu- 
tation. . , 
These observations are not complete enough to establish the 
limit of automaticity. In one instance, however, I traced the 
beating of the pulsatile organ in the amputated leg of an adult 
Ranatra through a period of twenty-six hours and twenty min- 
utes. The duration of beating in an amputated leg is probably 
. greatly affected by circumstances, and it may, therefore, continue 
longer than in the case just cited, or stop sooner, according to 
circumstances, 
The pulsating organ continues its beating even when sliced 
portions of the legs are used instead of whole legs. It was cut 
in two, and the posterior part, which was attached to a fragment 
of the leg, still continued to beat. 
One set of observations on an amputated leg, that fairly repre- 
sents the others, is given below in detail : 
On Oct. 3, 1883,-the front ieg of an adult Ranatra was put 
under observation at 1.45 P.M. The pulsations were regular from 
135 to 140 per minute. After watching for ten minutes the leg 
was cut off close to the body witha sharp razor. During this 
Operation the eye was kept upon the pulsating organ through the 
microscope. The only perceptible effect was a slight increase in 
the rate of beating, which was now found to be 146 per minute. 
For the next ten minutes the amputated leg was -under constant 
Observation. It continued beating during this time, towards the 
Close ata slightly diminished rate, say 135 pulsations per minute. 
t 2.05 P. M. I was called away. 
The next observation was made after an absence of one hour 
and thirty minutes, at 3.35 P. M.; the organ was then beating reg- 
ce ularly at 115 pulsations per minute. No change was observed up 
_ to 3.45 P. m., at which time the specimen was laid aside. 
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