4^6 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



Genus PRONOLAGUS new 



1867. Lepus Gray, Ann. Mag. Nat. Hist., 3d ser., xx, p. 223. 

 1899. Oryctulagiis Major, Trans. Linn. Soc. London, 2d ser.. vii, Zool., 

 p. 514, November, 1899. 



Type. — Pronolagiis crassicaiidains (Geoffroy). 



Geographical Distribution. — South Africa. 



Diagnosis. — Externally similar to Lcpns. Skull and teeth essen- 

 tially like those of Ronicrolagus except that audital bull?e are smaller 

 than foramen magnum, and anterior face of first lower premolar has 

 two reentrant angles. 



Sk}tU (pis. LXX\Tii, 2a. 2h : lxx\ti, 3). — The skull as a whole is 

 long and narrow. The anterior angle of the postorbital process is 

 entirely lacking or else is so intimately associated with the cranium 

 that the process appears as a triangle, one wdiole side of which is 

 attached to the cranium. Of the tw'o other sides one is directed out- 

 ward and somewhat forward and the other obliquely inward and 

 backward, forming the outer boundary of a posterior notch. The pos- 

 terior and only angle of the postorbital is pointed. The process, as 

 a whole, closely resembles that of Ronicrolagus, but it is relatively 

 as well as absolutely larger. 



It cannot be definitely stated whether the interparietal of Prono- 

 lagus is obliterated in adult life or not. In the single available 

 skeleton, which has evidence of being young, the sutures of this 

 bone are partially obliterated. 



The bony palate of Pronolagns is longer and narrower than in 

 most of the Leporidse, its least length equaling four times the 

 length of M^, though the palate of Ronicrolagus approaches it closely. 

 The incisive foramina are long and narrow, less triangular in outline 

 than they are in most of the other genera. Their greatest width, 

 taking both together, is much less than the length of the bony palate. 

 The horizontal plates of the palate bones are large, and form a little 

 less than half of the bony palate. The portion of the palate bone 

 that borders the maxilla caudad of the posterior edge of the bony 

 palate is developed to a greater degree than in any other genus except 

 Ronicrolagus, and aids in forming to a considerable extent the lateral 

 portion of the roof of the mouth just internal to the dental alveoli 

 and posterior to the bony palate. The choanee are considerably nar- 

 rowed, almost approaching the narrowness seen in Oryctolagiis, but 

 the pharyngeal vault is only moderately high. The posterior palatine 

 foramina are very small and would be scarcely noticeable were it not 

 for the well-marked grooves leading from them. These foramina are 

 located near the median line and not at the anterior external angles 



