The bow is a symbol of love and eternity that resonates through many different forms of wearable jewellery (which particularly shares the same family as the buckle). Notice the fleur-de-lis influence as well and the surrounding pearls to the hair memento. These are flourishes which make the attention to detail in this particular piece a very nice transition between the popular Regency and Victorian art styles.
The pearl surrounds and the delicacy of the gold work shows the Regency era and the boldness shows what would become more familiar during the middle 19th Century. The hair memento is overly busy as a weave and not as refined as it could be, but that may lean to the hair being of its actual owner, which was not the common practice of the time. Hair was given to jewellers in order to produce mementos, but most hair donated was unusable, hence hair bought from the Continent and surrounding Europe was more feasible in a construction and financial perspective.