THE PELAGIC OR SEA SNAKES. 235 



like, as only these, if at all, are exposed to the sea water, 

 and a very small notch on each side of the pointed rostral 

 shield of some permits the slight egress of these tips. 

 When out of their natural element, the tongue is brought 

 into more active service, for then the bewildered reptiles 

 require its assistance, and it is then seen to be exserted 

 as in land snakes. Their lungs extend the whole length 

 of the body to the anus, and by retaining a large supply of 

 air, these animals are enabled to float easily, as they do for 

 a long while on the surface of the calm tropical seas, not 

 only while sleeping, as mentioned in the chapter on hiber- 

 nation, but in pure enjoyment, and probably in the lazy 



« 



postprandial condition. 



As has been already stated, the eyes of sea snakes 

 are adapted to see better through the medium of water 

 than through the brilliant atmosphere of their native 

 latitudes. They are very small, and soon blinded by 

 light ; consequently, though among the swiftest and 

 most gracile of serpents in their native element, the 

 movements of the HydrophidcB on land are uncertain and 

 ' maladroit.' 



Some forty years ago. Dr. Theodore Cantor, F.Z.S., 

 devoted a good deal of time to the study of the pelagic 

 serpents, and wrote a somewhat detailed account of them 

 to the Zoological Society. His paper, published in the 

 Zoological Society Transactions, 1842, vol. ii., was considered the 

 most important that had as yet appeared. He, therefore, 

 has been one of our first authorities. Subsequently we are 

 indebted to Giinther, Dr. E. Nicholson, Gerard Krefft, and 

 Sir Joseph Fayrer for the results of their individual obscrva- 



