LÖNNBERG, ON A NEW ORYCTEROPUS FROM NORTHERN CONGO. 15 



odontoideus . Tliere are namely on the ventral surface near 

 the posterior end of the third and fourth cervical vertebrae 

 a pair of ridges, rudimentary hypapophyses, but on the lovver 

 surface of epistropheus there are two such pairs. The poste- 

 rior, which is even larger than that of the third vertebra, 

 belongs to epistropheiis itself but the anterior must be homo- 

 logised with rudiments of hypapophyses of atlas. The hind 

 end of these atlantic hypapophyses sit 11 mm. from the base 

 of proc. odontoideus and so 

 far reaches the atlantic 

 centre coalesced with epi- 

 stropheus. The rudimentary 

 hypapophyses appear to be 

 less developed in O. ajer and 

 quite absent on the 4th ver- 

 tebra. In the latter the para- 

 pophysis of either side of epi- 

 stropheus is not distinct but 

 in O. erikssoni it rises on the 

 lower surface as a crest in 

 continuation forward of the 

 diapop hysis (Fig. 5). On the 

 foUowing four vertebrse the 

 parapophyses become gradu- 

 ally larger and on the fourth 

 and sixth, but not on the 

 fifth, they have laterally an 

 anterior and posterior free 

 wing. On the fifth the po- 

 sterior of these is missing. 

 On the anterior margin of 

 the diapophyses of the third 

 to seventh vertebra there is 

 just outside foramen verte- 

 brce a flattened processus di- 

 rected forward and increasing 

 the posterior vertebrae. These 

 of O. ajer, which has even comparatively much smaller dia- 

 pophyses and parapophj^ses. Tubercular metapophyses are 

 present on the outer resp. lower side of the praezygapophyses 

 of 4th to 6th vertebrse. The 7th vertebra has, of course, no 



Fig. 5. Cervical vertebrse of O. eriks- 

 soni seen from below. V-» nat. size. 



m size 



from the anterior to 

 are missing in my specimen 



