382 



WILSON. 



Canal wall. 



EXPLANATION OF THE PLATES. 



Most of the drawings were made with the camera. The lenses referred to in 

 the description of the figures, are those of Zeiss, except when the focal distance 

 of the objective is given in inches. The drawings have been reduced to four- 

 sevenths original size. 



Common Reference Letters used in the Figures. 



a/, e. Afferent canal. 

 ait.f. c. Anlage of flagellated cham- 

 ber. 

 can. Canal. 



r. m. Solid anlage of flagellated 

 chamber. 

 cna. w.\ 

 {e.w.y. 

 c. ef. c. Central efferent canal. 



cu. Cuticle. 

 d. mem. Dermal membrane. 

 dcg.f.c. Degenerated flagellated 

 chamber. 

 ef. c. Efferent canal. 

 ect. {ec^ Ectoderm. 



> Ectodermal membrane. 

 (ec. mem.)) 



ec. un.p.f. Ectoderm of unpigmented 



pole. 



/. c. Flagellated chamber. 



for. e.g. Solid group of formative 



cells. 



f. Furrow. 



g. Gemmule. 

 g.f. Follicle of gemmule. 



g. sh. Sheath of gemmule. 



gr. c. Granular cell. 



In. sf. Intercellular space. 



/. Larva. 



