on the left is a spacer and perhaps, you do not understand well, a seal.
a seeger on the left would not serve anything because the locking is done by the wreath that pushes to the right the bearing and therefore the seeger would not have any influence; also the seeger in section is represented with only a dotted part (see some catalog or image on gooles)
the wreath pushes the bearing to the right until the latter touches the shouldering of the tree (the difference of diamtro) at that point the bearing cannot go either to the right or to the left and is therefore blocked axially
I have better focused the image is I realized that it is a skf support in two half (type snl)
the one on the left is a stop ring that is part of the bearing support and that axially blocks the bearing within the support.
axially locks all shaft support
you see it well in this image