The common carp provides an excellent example of non-mandibular teeth being used as the primary chewing apparatus. Pharyngeal teeth occur in the most fully developed forms of the Cyprinidae and Cobitidae, although many other groups also show some degree of abrading or triturating ability with some part of the gill bars. In carp, the lower ends of the gill bars have a well developed musculature which operates two sets of interdigitating teeth so as to grind plants into small pieces before swallowing them. The grinding presumably increases the rather small proportion of plant cells which can otherwise be successfully attached by digestive enzymes.