No. 2.] THE SPERMATOGENESIS OF LUMBRICUS. 297 



DESCRIPTION OF PLATES. 



All figures are magnified about 1,600 diameters, except Fig. i, Plate XIX. 

 Figs. 1-6, 9-33, 35, 37, 38, 43, 43A, 45, and 47 are from preparations fixed with 

 Hermann's fluid ; Figs. 7 and 8 with picric acid ; Figs. 34, 36, 39-42, 44, and 46 

 are from preparations fixed with chromic acid. 



All figures save i, 7, 8, 44, and 46 are from teased preparations ; the others 

 from sections. 



In all figures the following letters have the same meaning : 



