CROCODILES. 51 



was hitherto supposed. And for this reason* 

 Strictly aquatic animals, which use their limbs 

 in swimming, have commonly adopted the plan 

 of increasing the length of the hand and foot by 

 adding to the number of these little phalangeal 

 or finger bones, as witness the old Fish Lizards, 

 the Turtle, arid the Whales among the mammals. 

 The inference is, then, that the temporary pre- 

 sence of similar additional bones in the hand 

 of the developing Crocodile is a reminiscence of 

 an ancient swimming organ long since obsolete. 

 That it was never completely paddle-shaped, as 

 is the turtle or whale, we may be sure, inasmuch 

 as both these are too highly specialised ever to 

 be reduced again to the normal hand or foot from 

 which they were derived. That the inference 

 will some day be abundantly proved by the dis- 

 covery of some " new " fossil, we may predict 

 with tolerable safety. 



Whether these long-handed ancestors were 

 really more aquatic in their habits, or simply 

 used the limbs more than the tail in swimming, 

 we cannot of course say. But we have positive 

 evidence to show that a very near ally of the 

 living Crocodiles actually did exchange the am- 

 phibious for a purely aquatic life. 



The creature in question (Geosaurus suevicus) 

 has long been known from fragments obtained 

 from the Jurassic, but the intensely specialised 

 iharacter of the animal has only recently 

 (1892) come to light through the researches 

 of Dr Fraas, a German naturalist. He has 

 shown us that it resembles its contemporaries 

 of the Jurassic in that the hind-limbs are 



