New Species of Aplodontia. 323 



einzigen Exemplar verstiimmelt sein, obgleich es den Anschein 

 hat, als sei er unverletzt. Der Schadel zeigt, mit der von 

 Baird gegebenen Abbildung verglichen, sich darin auffallend 

 verschieden dass die obere Backzahnreihe nicht aiimillendkiirzer, 

 sondern ganz gleich ist der Entfernung der Schneidezabne von 

 den Backzahnen, dass der Ansscbnitt hinter dem Processus zygo- 

 matics des Scbliifenbeins ein viel gros*erer ist, das Foramen 

 men tale weiter nach vorn, die hintere otfnnng des Canalis infra- 

 maxillaris weiter nach hinten liegt und letztere von oben sichtbar 

 ist, dass ferner der Processus coronoideus an seiner Basis breiter 

 erscheint. Icli werde daher wegen dieser Unterschiede, bis die 

 Identitiit oder Verscbiedenheit der Thiere festgestellt sein vvird, 

 das Californisclie als H. leporinus var. Califoruicus bezeichnen." 



The mere existence of the above description of an Aplodontia 

 which is stated to have come from California, at once raises the 

 question of its identity with the present species. If reasonable 

 grounds exist for the belief that the two forms are not separable, 

 Peters's name Califoruicus must of course be accepted as the pro- 

 per specific name for the subject of the present paper. To deter- 

 mine this point, it is necessary to review somewhat in detail the 

 characters attributed to the Berlin animal. 



Peters's comparisons, it must be remembered, were based wholly 

 on Baird's description and plate. Baird's plate of the skull is a 

 fairly good one, and shows quite accurately most of the points 

 spoken of by Peters. 



The cranial differences mentioned by Peters are : 1st, that the 

 upper molar series of teeth is of the same length as the distance 

 between the molars and incisors, instead of being considerably 

 less ; 2d, that the post-zygomatic notch is much larger ; 3d, that 

 the mental foramen is farther forward ; 4th, that the posterior 

 opening of the inframaxillary canal is farther behind and is visi- 

 ble from above ; and, 5th, that the coronoid process appears 

 broader at its base. 



The first point relates to the length of the upper molar series 

 as compared with the length of the muzzle — a character which 

 in both species varies with the age of the animal. In the adults 

 of both the muzzle is considerably longer than the molar series, 

 while in the young it is equal to or even shorter than the molar 



