48 



THE BRITISH WOODLICE. 



SURFACE VIEWS. 



Gcafn 



forming 

 dwBiaM 



derm 



Pro- 

 ectodea 



Pro- . 

 etutodehd 



OPTICAL SECTIONS. 



fflarfoder/7? 



FIG. 25. 



fflasfodeD 

 (complete) 



Ectoderm 

 Mesoderm, 

 JFrzdoderm, 



gndoderm 

 ' fermuiy 

 mid-gut 



Eudiment 

 of nerve cord 



/tudwie/iti 

 (i)ffmd-guly 

 (st) Mid-guts 

 (3)Fore-gut 



FIG. 3] 



Mid-gut 

 ... Anus 

 /tout-gut 



"fatlsoftte 

 Sody cavity 



THE DEVELOPMENT OF A WOODLOUSE {Porcellio SCaber), AFTER ROULE. 



Figs. 24, 26, 28, 30, are Surface Views, and figs. 25, 27, 29, 31, which 

 indicate slightly later stages respectively than the others, are of eggs seen in Optical 

 Section. 



