According to recently published phylogenetic definitions, the term Lagomorpha is best restricted to the pika-rabbit clade (viz, the crown-clade) and the old name Duplicidentata is applied to the stem-group that includes Lagomorpha.    From Wordnik.com.  [Archive 2006-05-01] Reference

They have also a well-developed bony palate, which in the Duplicidentata is imperfect, forming in fact but a narrow bridge from one jaw to the other.    From Wordnik.com.  [Natural History of the Mammalia of India and Ceylon] Reference

Dentition of Hare Sub-order Duplicidentata.    From Wordnik.com.  [Natural History of the Mammalia of India and Ceylon] Reference