THE COMMON FROG. 



51 



present an analogy with serpents, from their 

 long and elongated bodies, and from the 

 utter absence of limbs. 



There are, however, but very few snakes 

 (the " roughtails " UropeltidtZ and the Tor- 

 tricidce) which have long bodies and very 

 short tails. 



It is rather the singular family of lizards, 

 Amphisbe7iidce (with one exception com- 

 pletely limbless) that the Ophiomorpha 

 resemble. 



These Amphisbenians have a softer skin 

 than any other Saurians except chameleons. 

 It is also marked in grooves which are 

 arranged in transverse rings. They have 

 an exceedingly short tail which is blunt, 

 so that, the head being small, one end of 

 the body is as large as the other. 



The Ophiomorpha also have the body 

 marked with numerous transverse grooves 

 or rings ; they are utterly devoid of limbs, 

 and the head is scarcely, if at all, larger 

 than the hinder end of the body. 



These creatures burrow beneath the soil 

 (which habit increases their resemblance 

 to earthworms) and feed on worms and 

 other small animals and mould. 



To turn now to another aspect of our 

 subject, let us consider the relations of the 

 Frog to past time. If, extending our survey 

 over the records of past epochs, we search 

 the tertiary' and all other rocks above the 



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