1908-9. | THE HABITS OF PLETHODON CINEREUS ERYTHRONOTUS. 471 
Two habits of Plethodon deserve notice as being of rare occurrence 
among Urodeles. When excited it occasionally aids its progress by 
leaping. In such cases as have been observed under conditions that 
admitted measuring the length of the leap it has been found about equal 
to the length of the animal’s body. If the animal is running on a rather 
even surface it lands on its feet and continues the run having gained by 
its leap; but it will just as readily leap into difficulties. Held in the open 
hand it will frequently leap off, no matter what may be the height of the 
hand above the ground. In jumping the back is slightly arched and the 
front limbs with most of the trunk are raised in the air to about the height 
of one centimetre; then with a snap the tail is slapped against the surface 
over which the animal is moving and the body sharply straightens and 
shoots forward. The whole movement is so rapid that it cannot be 
distinguished with certainty whether the limbs aid in the leap. Two 
things suggest that they do; it is difficult to imagine a force to raise the 
anterior part of the body to the height it attains if it does not chiefly 
lie in a spring given by the anterior limbs. The posterior limbs are even 
stouter and are in a good position to aid in the forward propulsion. The 
young as well as adults possess this power of leaping, indeed the only 
specimen observed to give a succession of leaps, three in fact, was one of 
24 mm. ‘The explanation of the greater development of the posterior 
limbs in the later larval stages, noted by Montgomery (’o1), may lie in 
this. habit. In this connection Cope (’89), says: ‘‘It frequently climbs 
to the summit of low vegetation, from which it springs by a sudden straight- 
ening or curvature of the body, as the case may be, in the manner of.a 
caterpillar.” The curvature and straightening in leaping are evident; 
the climbing of low vegetation to leap from it has not come under obser- 
vation. 
The second noteworthy habit is also connected with escaping 
enemies. Plethodon will sometimes break off a portion of its tail. Ttwo 
things suggested the existence of this habit before it was actually observed. 
In searching for Plethodons in decaying logs not infrequently as the cover- 
ing is lifted the animal will be found crawling stealthily away from the 
bit of tail that is making itself very conspicuous by its violent movements. 
This will occur at times when so little force has been used in picking apart 
the log that it is difficult to conceive how the piece could have been broken 
or pinched off. Again about 10% of all specimens found show the end 
of the tail in the process of regeneration, raising the suspicion that it is 
a mutilation out of the ordinary. On one occasion when a young Pleth- 
odon had been repeatedly touched by a small rod it suddenly gave a 
jump breaking off at the same time the terminal third of its tail. Two 
