Jaws of the Hare
You can see the teeth of the hare in the cutaway of the jaws. Note the “clipping”-oriented incisors, with the grinding-oriented molars. These are very similar to rodent teeth, having continually-growing incisors covered with enamel on the anterior surface, but with exposed dentine on the posterior surface. As dentine wears away much more easily than enamel, it serves as a “self-sharpening” system to keep the teeth in gnawing-condition.
Despite these similarities, the teeth of rodents and lagomorphs are the result of convergent evolution, rather than being closely related. The difference that first led scientists to believe this (before it was proved by analysis of the inner-ear bones and other anatomical features, and, much later, genetics) is that lagomorphia are far more herbivorous than rodentia, and as such, do not have pre-molars, or any evidence of having had them. Their palate anatomy and digestive tract differs significantly because of this.
The Handy Natural History. Ernest Protheroe, 1910.