40 , MYRIAPODA 



The mode of progression in the Myriapods differs considerably, 

 as might be expected in a class in which the number of legs 

 varies to such an extent. The swiftest among them are the 

 Scutigeridae with their long spider-like legs. The Scolopendridae 

 are also able to move with considerable rapidity, and are also 

 able to move tail forward almost as well as in the ordinary 

 manner. Where there are such a number of legs it becomes a 

 curious question as to the order in which the animal moves 

 them ; and though several people have endeavoured to find this 

 out, the number of legs to be moved and the rapid movements 

 have rendered accurate observation impossible. 



Some years ago Professor E. Ray Lankester tried to study the 

 order in which the legs of Centipedes moved, and came to the 

 conclusion (recorded in an amusing letter in Nature, 23rd May 

 1889) that if the animal had to study the question itself, it 

 would not get on at all. He finishes his letter with the follow- 

 ing verses : 



A Centipede was happy quite 



Until a toad in fun 



Said, " Pray which leg moves after which ? " 



This raised her doubts to such a pitch, 



She fell exhausted in the ditch, 



Not knowing how to run. 



The progression of Millepedes is much slower than that of 

 the Centipedes, and it is remarkable that when the animal is in 

 motion a sort of wave runs down the long fringe-like row of feet. 

 I have endeavoured to make out this motion, but have never 

 been able to understand it satisfactorily. My belief was that 

 the feet were moved in sets of five. 



This wave-like peculiarity of motion is described in a curious 

 old book. An Essay tovjards a Natural History of Serpents. 

 Charles Owen, D.D. London, 1742: "The Ambua, so the 

 natives of Brazil call the Millepedes and the Centipedes, are 

 serpents. Those reptiles of thousand legs bend as they crawl 

 along, and are reckoned very poisonous. In these Multipedes the 

 mechanism of the body is very curious ; in their going it is 

 observable that on each side of their bodies every leg has its 

 motion, one regularly after another, so that their legs, being 

 numerous, form a kind of undulation, and thereby communicate 

 to the body a swifter progression than one could imagine where 



