TROPIDONOTUS 169 



being torpid, and resume activity very early in the 

 spring. 



In the Alemtejo, according to Gadow, when 

 during the rainless and hot summer the small rivers 

 have nearly dried up, these snakes collect in great 

 quantities in the remaining stagnant and muddy 

 pools, and, as the stock of suitable fish gets ex- 

 hausted, are often reduced to a deplorably emaciated 

 condition. By the month of August they have 

 become so thoroughly aquatic that they cannot be 

 kept alive in dry surroundings for twenty-four hours, 

 apparently dying from some kind of cutaneous 

 suffocation. The same observer once caught a 

 Viperine Snake in a ditch whilst it was swallowing 

 an eel of nearly its own length. 



Some specimens show so great a superficial re- 

 semblance to the Common Adder, Viper a bents, 

 which, however, being a more northern reptile, very 

 seldom occurs in the same localities — that this snake 

 well deserves its name Viperinns. A celebrated 

 herpetologist, Constant Dumeril, was once himself 

 deceived by this resemblance and bitten by a Vipera 

 berus which he had picked up in the Forest of Senart, 

 near Paris, believing it to be a Tropidonotus viperinus ; 

 whilst, conversely, a specimen of the harmless snake 

 was killed in mistake for a Viper by no less an expert 

 than Dr. Viaud-Grandmarais. 



Breeding. — This snake pairs in March and April, 

 and sometimes again in the autumn ; but the eggs 



