326 New Species of Aplodontia. 



animal known as yet from the single specimen in the Berlin Mu- 

 seum, or it may prove to be a case of abnormal individual varia- 

 tion. Be this as it may, no trace of it has been found in any 

 other individual of the genus thus far reported. 



Recapitulating, it is found that some of the supposed differ- 

 ential characters attributed to the Berlin specimen are due to 

 age ; that others fall within the limits of normal individual vari- 

 ation ; while others still are either really distinctive or markedly 

 abnormal. To the latter category belongs the white flank-patch, 

 the most important if not the only external peculiarity. If Pe- 

 ters's description is reasonably accurate, the following cranial 

 characters are distinctive: 



1st. Size of post-zygomatic notch. 

 2d. Position of mental foramen. 

 3d. Position of dental foramen. 

 4th. Size of infraorbital foramen. 

 5th. Size and form of audital bullae. 

 6th Size and form of pterygoid fossa. 



It may not be out of place here to allude to the geographical 

 source of the Berlin specimen. The only information given by 

 Peters on the subject is that the animal came from " aus den 

 Gebirgen Californiens ;" and since at the time this paper was 

 written (22 years ago) the term 'California' was somewhat 

 vaguely applied by most Europeans to the whole west coast re- 

 gion of the United States, it seems safe to assume that very little 

 certainty attaches to this part of the record. 



In view of the above facts, brought to light by a somewhat 

 critical analysis of Peters's description, with an ample series of 

 both the Washington and the California animals at hand for 

 comparison, the conclusion arrived at is that the Berlin specimen 

 is widely distinct from the California Aplodontia herein de- 

 scribed ; that it shares several points in common with the original 

 species [A. rufd) ; but that, unless Peters's description is grossly 

 erroneous, it possesses certain distinctive characters which are of 

 sufficient taxonomic importance to demand the establishment of 

 a new genus for its reception. 



In concluding this part of the subject it is necessary, perhaps, 

 to say a word in regard to the summary manner in which Peters's 



