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E. A. ANDREWS. 



The extreme tip to the left, as well as two intermediate 

 regions, are lower and are bent alternately down, up and down. 

 Thus one sees on the right only the top of the ridge, then part 

 of its upper or distal surface, then the top, then part of its lower 

 or proximal surface, then the top again and finally the upper 

 surface at the end. By this mode of bending as a warped sur- 

 face the edge of the pocket, or ridge, toward the observer is 

 longer than the anterior edge, which is the mouth, so that the 

 same condition is found as in higher crayfish and the sperm 

 pocket is like an elastic coat pocket which should have its mouth 

 bent in an S and its bottom pulled out into an S with longer 

 loops, after the fashion of a mesentery that has a shorter origin 

 and a longer line of attachment. Seen on the outside (Figs. 2 

 and 3) this greater bending of the internal than of the external 



Fig. 7. 



limiting edge is evident and variable. In old well-marked annuli 

 the pocket (Fig. 2) drops down from its mouth in a long sweep 

 toward the base of the annulus and then sweeps up above the 

 suture toward the summit to return again toward the median end 

 of the suture. In other cases (Fig. 3) the pocket is less drawn 

 out toward the summit and stands more at right angles to the 

 surface. When more magnified such a receptacle seen from the 



