OKYCTOLAGUS 487 



front legs it does not extend beyond wrist, the dorsal surface of 

 which is occasionally marked with whitish or white. 



Skull. — -General form of skull slender, typically leporine, the 

 rostrum produced, the occipital region strongly bent downward. 

 Dorsal profile essentially straight from tip of nasals to front of 

 brain-case, then slightly convex and strongly deflected to posterior 

 edge of occiput ; ventral profile nearly parallel to dorsal profile, 

 but downward curve beginning further forward, about at level of 

 anterior extremity of postorbital process ; occiput flatly truncate 

 at right angles with axis of brain-case, therefore obliquely to 

 main axis of skull. Brain-case short-ovate in outline when 

 viewed from above, its anterior extremity sharply defined by 

 very deep postorbital constriction, its postero-lateral outline 

 somewhat distorted by slightly projecting mastoid and auditory 

 region. Interparietal rhomboidal or ligulate, its length usually 

 about half width. No sagittal crest ; lambdoid crest represented 

 by a low ridge which curves abruptly backward at level of outer 

 extremities of interparietal to form the outline of a sharply 

 defined, somewhat elevated, bony shield lying on dorsal surface of 

 supraoccipital and extending backward to edge of abrupt trunca- 

 tion ; the general outline of this shield is squarish, but the 

 posterior border is occasionally concave and the lateral borders 

 may be convex. Posterior aspect of brain-case a broadly 

 rounded arch slightly wider than high, the conspicuous, elongated 

 paroccipital processes descending below level of lip of large 

 foramen magnum, and closely applied to posterior surface of 

 auditory bulla}. Floor of brain-case marked transversely by 

 persistent suture between basioccipital and basi sphenoid ; behind 

 this suture the basioccipital widens slightly, then narrows 

 abruptly at front of condyles, its median region with wide 

 longitudinal groove ; auditory bulla flask-shaped, moderately 

 inflated, with well developed straight neck, the main axis of 

 bulla nearly parallel with posterior surface of occij^ut, though 

 directed slightly outward, the sub-circular meatus plainly visible 

 when viewed from above ; transverse diameter of bulla about 

 equal to that of basioccipital at region of greatest width between 

 bullce ; height including tube neax'ly twice transverse diameter. 

 Interoi'bital region flat, somewhat depressed, its width about 

 equal to that of rostrum a little in front of middle ; postorbital 

 process slender, crescentic, bent downward at each extremity, the 

 posterior limb decidedly longer than anterior limb though rarely 

 coming in contact with brain-case ; anterior limb occasionally 

 fusing irregularly with frontal, zygoma rather slender, its upper 

 edge narrow throughout and not flattened or everted along 

 anterior half as is usually the case in the European species of 

 Lepus. Rostrum slender, its depth to anterior rim of alveolus of 

 first cheek-tooth noticeably less than distance from latter point 

 to front of incisive foramen, nearly parallel-sided when viewed 

 from the side, tapering slightly when viewed from above or 



