THE BULLFROG 121 



to note that in the mud-tortoises we have the bony 

 plates of the shell greatly reduced and surrounded by 

 soft skin, while in two kinds of frogs the skin of the 

 back becomes furnished with bony plates which are 

 complete representatives of those of the tortoise, though 

 much smaller. 



Again, the turtle is exceptional among reptiles for 

 such an extension of some of the skull bones as to give 

 the brain case a deceptive appearance as to size. The 

 very same thing is also found in two members of the 

 frog's order. How cautious it is necessary to be in 

 attributing such similarities to special inheritance has 

 been strikingly shown by the discovery in an African 

 animal belonging to the rat's order (Kodentia) of the very 

 same kind of extension of -^e bones of the skull. 

 Building upon such resemblances it might be supposed 

 that frogs were the parents of tortoises, efts of lizards, 

 and the worm-like ophiomorpha of snakes. But here 

 we hope enough has been said to show that such a view 

 is utterly false, as also to impress on our readers a 

 wholesoDie caution as to wild speculation and hasty 

 generalisation in matters zotilogical. 



While keeping our minds free from prejudice and 

 ready to receive all and any truth which may be demon- 

 strable, we must be scientifically exacting in our demand 

 for evidence with respect to all hypotheses put before us. 



