428 Maine; agricui^turai. sxperime;nt station. 1912. 



Description o^ Figure^s. 



Figures 457 to 474 were drawn with the aid of a camera 

 lucida. All iigures have been reduced one-half in reproduction. 

 The approximate magnification of each figure, as reduced, is 

 given below. 



The following characters have the same meaning in all the 

 figures : 



O — Outer muscular layer. 



I — Inner muscular layer. 



T— Tubular glands. 



E — Unicellular epithelial glands. 



G — Glandular groove. 



