[Linear measurements of the bones of Lepus brachyurus brachyurus Temminck, Pentalagus furnessi Stone and oryctolagus cuniculus Linnaeus (JW-NIBS). I. On the cranium and ossa trunci (author's transl)].

The Ossa cranii and ossa trunci in Lepus brachyurus brachyurus, Pentalagus furnessi and Oryctolagus cuniculus (strain : JW-NIBS) were investigated morphologically and osteometrically. The number of coccygeal vertebrae is 10-12 in Lepus, 10-11 in Pentalagus and 15-17 in JW-NIBS. The number of upper cheek teeth of Pentalagus is six on one side. Therefore, Lyon's view that the number of upper cheek teeth of Pentalagus is five may not be applicable to use as one of the discriminative characteristics. The sizes of orbit and tympanic bullae in Pentalagus are remarkably small. The length of neurocranium and the inner breadth of caudal surface of vertebral foramina in cervical, thoracic and lumber vertebrae in JW-NIBS are small than those in Lepus and Pentalagus. Among three genera, there are conspicuous differences in shapes of spinous and transverse processus in the lumber vertebrae. The coefficient of variability of the measurements in JW-NIBS is smaller than that in Lepus.