Ch. XXI.] SAURIANS OF THE LIAS. 425 



of tlieir own predaeeous race, or of fishes found fossil in the same 

 beds. 



For the last twenty years, anatomists have agreed that these ex- 

 tinct saurians must have inhabited the sea : and it was urged that as 

 there are now chelonians, like the tortoise, living in fresh water, and 

 others, as the turtle, frequenting the ocean, so there may have been 

 formerly some saurians proper to salt, others to freshwater. The com- 

 mon crocodile of the Ganges is well known to frequent equally that 

 river and the brackish and salt water near its mouth ; and crocodiles 

 are said in like manner to be abundant both in the rivers of the Isla 

 de Pinos (or Isle of Pines), south of Cuba, and in the open sea round 

 the coast. More recently a saurian has been discovered of aquatic 

 habits and exclusively marine. This creature was found in the Galapa- 

 gos Islands, during the visit of H.M.S. " Beagle " to that archipelago, 

 in 1835, and its habits were then observed by Mr. Darwin. The 

 islands alluded to are situated under the equator, nearly 600 miles to 

 the westward of the coast of South America. They are volcanic; 

 some of them being 3000 or -1000 feet high; and one of them, Albe- 

 marle Island, 75 miles long. The climate is mild ; very little rain falls ; 

 and in the whole archipelago there is only one rill of fresh water that 

 reaches the coast. The soil is for the most part dry and harsh, and 

 the vegetation scanty. The birds, reptiles, plants, and insects are, with 

 very few exceptions, of species found nowhere else in the world, although 

 all partake, in their general form, of a South American type. Of the 

 mammalia, says Mr. Darwin, one species alone appears to be indigenous, 

 namely, a large and peculiar kind of mouse ; but the number of lizards, 

 tortoises, and snakes is so great, that it may be called a land of reptiles. 

 The variety, indeed, of species is small ; but the individuals of each 

 are in wonderful abundance. There is a turtle, a large tortoise 

 (Testudo Indicus), four lizards, and about the same number of snakes, 

 but no frogs or toads. Two of the lizards belong to the family Iguanidce 

 of Bell, and to a peculiar genus (Arnblyrlujnclius) established by 

 that naturalist, and so named from their obtusely truncated head and 



Fig. 459. 



Arnblyrhynchui cristatus, Bell. Length varying from 3 to 4 feet. The only existing marine 



lizard now known. 



a. Tooth, natural size and magnified. 



