106 COPEIA 



I now infer that it lies in wait and leaps at its prey 

 like a cat at a sparrow. 



When I look at the diminutive legs of this sala- 

 mander—legs hardly thicker than a pin, and devoid 

 of modernized, condylarthrous joints — I marvel that 

 they should be able to propel the squat, snaky body 

 for a distance of twice its length through the air. It 

 seems mechanically incredible, even though the salta- 

 tory impulse doubtless come more from the myocom- 

 mata rather than from the minute muscles of the 

 limbs. 



With all of this in mind, why could not some 

 of the temnospondylous Stegocephalians, such as the 

 Permian Cacops, or Dissorophus, or the African 

 Triassic Braehyops, have begun the jumping habit? 

 And may not the ancestors of the frogs and toads 

 have been excellent leapers even before they lost their 

 loose-hung bodies and permanent tails? None of 

 them, surely, had less of a "jumping build" than 

 Plethodon. Furthermore, if the direct, as well as 

 the collateral ancestors of the Anura were large crea- 

 tures, it is easy to believe that decrease in size and 

 weight would be a necessary concomitant to improved 

 saltatory power during the tailed epoch. Plethodon 

 approximates a crocodilian in build; if it were as 

 large and heavy it probably could not jump. 



All kown Anura, even as far back as the Juras- 

 sic, are extremely modernized, and are separated by 

 a wide evolutionary gap from the Palaeozoic amphibi- 

 ans. My intention is merely to suggest that such a 

 form as Cacops may well have been a leaper; and 

 to draw an analogy between the modern urodeles, in 

 which the saltatory habit is doubtless an incipient 

 land-living development, and the primitive temnos- 

 pondyls, which, as recently suggested, * may possibly 

 be the forbears of the leaping frogs and toads. 



R. C. Murphy, 



Brooklyn, N. Y. 



'Gregory, W. K., The American Naturalist, Vol. 51, 1917, p. 317. 



