204 C. F. CURTIS RILEY 



pachypus, appears to be somewhat akin to the death-feint, or 

 to the hypnotic state already described. The following quota- 

 tion taken from Gadow (1901, p. 156) gives a good description of 

 the posture assumed by these toads during the response: 



"When these toads are surprised on land, or roughly touched, they 

 assume a most peculiar attitude. * * * The head is partly thrown 

 back, the limbs are turned upwards with their under surfaces outwards, 

 and the whole body is curved up. * * * The creature remains in this 

 strained position until all danger seems passed." 



The following interesting description of the death-feigning in- 

 stinct among toads and frogs is given by Dickerson (I.e., p. 34) : 



"Many of the Salientia play dead in response to an unexpected tactual 

 stimulus. The common toad will often hold the legs tight against the 

 body and inhibit all movement — even the breathing vibrations of the 

 throat — when seized by a dog or other enemy. The leopard frog may 

 stretch the legs backwards stiff and straight, fold the arms on the breast, 

 and inhibit the breathing movements. It certainly looks like a dead frog 

 as it lies motionless in one's hand for fully a minute; suddenly, with a 

 lightning movement, it is gone before the hand can be closed over it. The 

 cricket frog plays dead in water. Taking a position with arms and legs 

 rigid and throat collapsed, it floats about helplessly like any stick or leaf." 



Dickerson (I.e., 87-88) considers the death-feigning response of 

 the toad to be a protection to the animal. She states that, 



"The toad is fitted for his place in life by what he does, as well as by 

 what he is. Let an enemy seize him roughly, and he is a dead toad. 

 'Playing dead' saves him many a time. He will lie on his back with 

 scarcely any perceptible motion for minutes at a time. Even the breath- 

 ing movements seem to be suspended. Suddenly one leg is thrust out, 

 then another, the eyes open wide, and in an instant more, the toad has 

 turned over and is ready for new emergencies. Whether this habit is 

 a protective instinct, or whether the toad really is insensible from fright 

 during the time that it 'plays dead,' the resulting protection is the same, 

 for, as a rule, animals that feed upon living food associate motion with 

 life so firmly that they pay no attention to a motionless creature." 



Facts similar to those described by Dickerson have been ob- 

 served by Holmes (I.e., pp. 59, 60, 61), who considers this 

 immobile condition of the frog to be an hypnotic state. Accord- 

 ing to this author the position assumed varies at different times. 

 Some individuals are more easily hypnotized than others, and 

 the duration of the hypnotic state also varies in different frogs. 

 Sometimes a frog will remain immobile for hours. A frog may 

 be aroused from its condition of hypnosis by some sudden 

 stimulus, and the awakening often occurs immediately. 



Sometimes when removing the young toads from the aquarium 

 jar to the experimentation dish, the writer observed that the 



