HABITS OF CRYPTOBRANCHUS ALLEGHENIENSIS. 1 3 



Reese, '05) ; it also makes possible the capture of rather large 

 animals as food. No attention is ordinarily paid to pieces of meat 

 unless they are in motion, or attract notice by actual contact. 

 The rocks under which Cryptobranchus lurks also afford cover 

 for its prey, hence a food supply may be obtained without leav- 

 ing shelter. 



Although I have handled the animals very often and without 

 caution, I have never been bitten by them. A specimen con- 

 fined in the Zoological Laboratory of the University of Michigan 

 is said to have tried to bite several persons ; this happened only 

 after it had become accustomed to its surroundings and to the 

 presence of people about it ; probably it was only the usual feed- 

 ing reaction, which had previously been inhibited by discomfort 

 or fear. 



Slime Production. — The surface of the body is at all times 

 slimy enough to be extremely slippery, making the animal diffi- 

 cult to hold except when grasped by the neck. This constant 

 secretion is of value to the animal in protecting the skin from 

 abrasion in gliding over a rough rock, and perhaps also from 

 parasites. But when a hellbender is injured or seized and forcibly 

 held, an abundant flow of sticky, whitish, gelatinous slime, resem- 

 bling the " milk " from the broken end of a milkweed stem, 

 breaks out over the entire body or sometimes only from the tail. 

 This slime causes a smarting sensation when it comes in con- 

 tact with the freshly-cut surface of the skin. 



Profuse slime production is at least indirectly a result of mechan- 

 ical stimulation, though probably under the control of the ner- 

 vous system, and associated with fear. 



Reactions to Mechanical Stimuli. — The adult Cryptobranclius is 

 strongly thigmotactic, seeking crevices under rocks or an angle 

 of the aquarium in which it is confined — a result not entirely due 

 to a negative reaction to light. It may even force its way under 

 a stone of considerable size where no crevice exists, lifting the 

 stone bodily in the water. 



A shock or jar in the water sometimes causes a quick jerking 

 movement, and withdrawal under a convenient cover ; but the 

 adult reacts far less readily to a shock than the larva. 



When forcibly held, the animal wriggles actively, and some- 



