S56 THE GREAT UNKNOWN. 



"sixteen or eighteen feet," and these are by no means 

 extravagant. 



On the whole, I am disposed to accept this case as that 

 of a true serj^ent — jjerhaps the Boa murina, one of the 

 largest known, and of very aquatic habits — carried out 

 to sea by one of the great South American rivers, and 

 brought by the gulf stream to the spot where it was seen. 

 If I am warranted in this conclusion, it afibrds us no help 

 in the identification of the great unknown. 



I do not attach much value to the assertions of obser- 

 vers, that the head of the animal seen by them respectively 

 was "undoubtedly that of a snake." Such comparisons 

 made by persons unaccustomed to mark the characteristic 

 peculiarities which distinguish one animal from another, 

 are vague and unsatisfactory. Their value, at all events, 

 is rather negative than positive. For example ; if a per- 

 son of liberal education and general information, but no 

 naturalist, were to tell me he had seen a creature with a 

 head " exactly like that of a snake ;" I should understand 

 him, that the head was not that of an ordinary beast, nor 

 of a bird, nor that of the generality of fishes ; but I should 

 have no confidence at all that it was not as like that 

 of a lizard as of a serpent ; and should entertain doubts 

 whether, if I shewed him the form of head, even of cer- 

 tain fishes, he would not say, — " Yes, it was something 

 like that." 



There does not seem, then, any sufficient evidence that 

 the colossal animal seen from the Dcedalus, and on other 

 occasions, is a serpent, in the sense in which zoologists use 



