STRUCTURE AND CLASSIFICATION OP THE ARTHROPODA. 577 



APPENDIX. 



On the Movements of the Parapodia op Peripatus, Milli- 

 pedes, AND Centipedes. 



[Matter not contained in the article published in the ' EncyclopEedia 

 Britannica.'] 



I TAKE tlie opportunity of the issue of my article ' Arthro- 

 poda' as a reprint to add to it some drawings showing the 

 movement of the parapodia or legs of Onychophora, Diplopoda, 

 and Chilopoda. I was unable to introduce these into the 

 original article, and I now give them in the form of a plate 

 (PI. 42). They were made neai^ly twenty years ago in my 

 laboratory at University College, London, from living speci- 

 mens by Miss Stone. The live Peripatus (P. cap en sis) were 

 given to me by Mr. Adam Sedgwick; the Centipede, Scolo- 

 pendra subspinipes (Leach), was brought to me from 

 Barbadoesby Mr. Tracey; and the Millipede, Archispiros- 

 treptus pyrocephalus (L. Koch), I obtained from Mr. 

 Pocock. 



Of course, the attempt to fix and record, by the simple use 

 of eye and pencil, a phase of successional movement, such as 

 that exhibited by the series of legs of the Arthropoda or of 

 the Chffitopoda, is not altogether satisfactory at the present 

 day. We ought to have i-ecords of these phases taken by 

 photography and the instantaneous illumination of the electric 

 spark. But in the meanwhile the drawings, which were care- 

 fully and conscientiously made after repeated observation 

 and study, show some interesting facts. 



A fact which the drawings are not fitted to show is, that 

 the change of phase — that is to say, the alteration in the 



