Oldfield Thomas, Das Milchgebiss der Sugetiere. 217 



of scientific men that can be interested in it, the more chance there 

 is of evidence bearing- on the various disputed points turning up and 

 being properly observed and utilized. 



Althoiigb Dr. Schlosser does not definitely give in his adhesion 

 to any of tbe other theories that have been propounded in reference 

 to the homologies of the Mammalian milk-dentition, yet he is imable 

 to accept the view first put forward by Prof. Flower, and afterwards 

 supported by myself, that the diphyodoutism of the Mammalia is a 

 new development (Erwerbung), instead of being a remnant (Erbteil) 

 of the polyphyodontism found in the lower Vertebrates. He therefore 

 disagrees on the whole with the views advocated in the paper he 

 criticises, but as this involves matters of opinion, not ripe for final 

 proof or disproof, I do not propose to join issue with him on the 

 general question, and would only draw attention to two or three 

 points of detail which are more or less capable of practical proof. 



The most importaut of these oecur in the Anhang" to Dr. 

 Schlosser 's paper. There the author states Nach beiden Autoren ^) 

 reprsentieren die vor den echten Molaren auftretenden Backzhne 

 der Elephanten die persistent gewordenen Milchzhne und nicht etwa 

 die Prmolaren; und weiter ist nach diesen Autoren auch der vor- 

 derste Backzahn der Placentalier, wie beim Hund, Schwein, Pferd etc. 

 nicht als P', sondern als MP^ zu deuten 2). Ich kann diese beiden 



Ansichten gar nicht scharf genug bekmpfen Wie man ange- 



sichts dieser Verhltnisse von persistent gewordenen Milchzhnen 

 sprechen kann, ist mir absolut unerfindlich." 



Now the second of these two disputed opinions, that the anterior 

 non-changing premolar of the dog and others is a persistent milk 

 tooth is one which I at least have neither held nor expressed. On 

 the contrary the diagram of a generalized Eutherian Dentition, of 

 which Otocyon is quoted as au example (VIII" both on p. 454 and 

 on the plate to my paper) shows distinctly this tooth referred to the 

 permanent series, a view which I still hold, and see no reason to alter. 



1) The other author referred to is Mr. Jacob Wortman, whose work 

 Comparative Anatomy of the Teeth of the Vertebrata" 1886, I have unfor- 

 tunately not been able to refer to. 



2) I have translated these signs from the somewhat excentric notation 

 used by the Hensel school of German naturalists to that used and understood 

 by all other zoologists. In the time of Hensel, when it was supposed that 

 premolars, if lost, were always lost from before backwards, there seemed to 

 be a certain amonnt of reason for the reversed notation, but now that we know 

 this generalization to be unsure in many cases, the resulting notation might 

 surely be abandoned in the interest of clearness and uniformity. One of its 

 most distinguished adherents told me himself that he would have long ago 

 discarded it, had it not been the invention of Hensel, and that anything that 

 Hensel brought forward was sure to be good. Could blind devotion to authority 

 go further? 



