LÖNNBERG, ON A NEW ORYCTEROPUS FROM NORTHERN CONGO. 27 



OwEN 1 spöke even låter of the »compound tooth of the 

 Orycterope» and its »denticles» and compared the structure 

 with that found in »the teeth of the Myliobates and Chimce- 

 roids». But he added that »each denticle is developed accord- 

 ing to the same laws, and by as simple a matrix, as those 

 larger teeth in other mammals which consist only of dentine 

 and cement». Thus Duvernoy and Owen evidently regar- 

 ded these teeth as being compound. 



Flower and Lydekker - described the teeth of Orycte- 

 ropus as »made up of an aggregation of parallel dental sys- 

 tems» — — — etc. 



In his recent manual Max Weber speaks of »wurzellose, 

 säulenförmige Zähne ohne Schmelz, aber mit einem Mantel 



von Zement» — ■. He also compares the structure with 



that found in Myliohatis and Pristis, but adds that, according 

 to his opinion, the teeth of Orycteropus represen t »das ab- 

 errante Reduktionsprodukt eines urspriinglich schmelzfaltigen 

 Zahnes», and explains the proceeding in such a way that 

 the tooth löst »seine Schmelzbedeckung, wurde ein beständig 

 wachsender, wurzelloser Zahn mit Dentikelbildung, welche 

 täuschend Selachierzähne nachahmt». It appears thus as if 

 Weber assumed that the teeth of Orycteropus had developed 

 from some kind of highly specialised teeth with folded ena- 

 mel, then the enamel had been löst and the elements or parts 

 of the tooth formerly enveloped in the enamel-folds should 

 have formed »Dentikel» only containing dentine and each 

 with its own particular pulpa ^. 



This would have been a very extraordinary mode of 

 development, because it seems peculiar if a type of tooth 

 with folded enamel should through retrograde development 

 be able to lose completely the complicated enamel covering 

 without being simplified in other respects but still retain the, 

 through the folding of the former, existing enamel effected 

 subdivisions of the tooth. If a reduction of some parts of 

 the tooth takes place it is not probable that the other parts 

 remain unaffected by this proceeding. But this is not the 



^ Anat. Vertebr. Vol. III. London 1868, pag. 272—273. 



- An Introduction to the Study of Mammals. London 1891. 



' The author just quoted does not, however, seem to be satisfied 

 himself with this explanation as he adds : »Vielleicht diirfen wir den Oryc- 

 teropuszahn mit dem in Beziehung, bringen, was man Vasodentin nennt»^ 

 - — — . I think that this lies nearer the truth as will be seen below. 



