SEA SNAKES 



91 



Left, sea snake overgrown with barnacles. Right, a small portion of the skin enlarged, showing 

 hexagonal scales (not overlapping) and barnacles with bivalvular shells. The barnacles attach 

 themselves to the snakes as free-swimming larvts. 



with its thin forepart in search of the eels which constitute its only food. 



When a sea snake is emptied out from a net on to the deck it is com- 

 pletely helpless. It writhes and wriggles but does not get anywhere. The 

 ventral shields, which in snakes are normally an important means of 

 crawling, are in most sea snakes very degenerate or totally absent; and, 

 in addition, the hindpart of the body and the compressed, paddle-shaped 

 tail have a pronounced downward curve which, on land, causes the ani- 

 mal to turn over on its side. However, helplessness when on land, as we 

 shall shortly see, is not true of all sea snakes. 



For all their helplessness we handled our sea snakes with some respect, 

 seizing them behind the head with a pair of long tweezers and then 

 grasping them by the tail with the other hand. How dangerous they are 

 we do not know for certain, as the little information available is extremely 

 contradictory. On the one hand, careful experiments have shown that 

 the venom of sea snakes is ten times as toxic to certain animals as that 

 of the cobra. A dog, for example, died from a bite in less than an hour. 

 The effect of the venom of a sea snake, like that of a cobra, is to paralyze 

 the central nerve system, death being due to asphyxiation owing to the 

 paralysis of the respiratory system. The venom is particularly toxic to 



