l6o TURNER. 



Crustacea is the homologue of the archicerebrum (supra-oesopha- 

 geal ganglion) of the polychaete annelids. 



Clark University, South Atlanta, Ga. 

 September 14, 1898. 



REFERENCE LETTERS. 



CM., cells of the mushroom bodies. 

 S.Hf., stalk of the mushroom bodies. 



All figures were drawn with a camera. Figures 2 and 6 are drawn to the same 

 scale. Figures 3, 4, and 5 are drawn to the same scale, but are enlarged more 

 than 2 and 6. Figure r is enlarged more than any of the others. 



