ORYCTOLAGUS 



485 



the posterior liiiil) of which (except in certain domestic forms) 

 is alwcays free from cranium, persistence of sutures surrounding 

 interparietal, and the strongly narrowed choanpe, the width of 

 which, immediately behind palate, is noticeably less than least 

 length of palate. Teeth essentially as in Lepus, but incisors 

 both above and below less deeply implanted, and course of root 

 of upper tooth not visible on outer surface of premaxillary. 

 Cheek-teeth consisting of enamel cylinders tilled with cement 

 and dentine. In m-^ the cylinder is simple, its cross-section 

 elliptical. In the anterior upper premolar it is also simple, but 

 the anterior border is indented by longitudinal grooves appearing 

 as re-entrant angles on worn surface of crown. In all the other 

 cheek-teeth the cylinder is divided into two sections by a 

 re-entrant fold arising from inner side of maxillary teeth and 

 from outer side of mandibular teeth, in the former nearly 

 crossing the crown, in the latter completely crossing it, though 

 the two sections remain joined at their inner extremities 

 except in m.^, in which they are distinct throughout ; * anterior 

 section of first lower premolar indented by longitudinal grooves 

 on its anterior surface. 



Hcmarhs. — The genus OrycioJagus contains the domestic 

 rabbits and the wild rabbit of central and southern Europe. In 

 addition to the moz'e technical characters of the group its 

 members are readily distinguishable from the other Leposidse, 

 with which they are naturally associated, by the blind, helpless 

 condition of the young at birth. f 



ORYCTOLAGUS CUNICULUS Linnpeus. 

 (Syuouymy under subspecies.) 



Geographical distribution. — Northern Africa and southern 

 and central Europe, the details of distribution considerably 

 modified by human agency. 



Diagnosis. — Size smaller than in the European species of 

 Lepus (the Sardinian Lepus mediterraneits excepted), the hind 

 foot in dry specimens seldom exceeding 90 mm., the occipito- 

 nasal length of skull in largest individuals seldom more than 

 80 mm., ear from crown (dry) usually 70 to 80 mm., tail, including 

 pencil, about as long as hind foot, its under surface and edge 

 white, its upper surface blackish, usually grizzled with light 

 brown ; general colour above a grizzle of black and light bi-own ; 

 a distinct, dull buffy nape patch ; ear essentially concolor with 

 back though more finely grizzled, without distinct colour pattern, 

 the outer surface narrowly edged with black at tip ; underparts 



* The structure of the teeth may be most clearly understood by 

 examining the roots. 



t This character recurs in the American Sylvilagns and perhaps ako 

 in some of the less known genera. 



