52 ARKIV FÖR ZOOLOGI. BAND 14. N:0 4. 



the tail is about 37,6 % of the length of head and body. 

 According to Peters exact measurements the same relation 

 in his specimen is 38,3 %, thus practically the same. The 

 tail of the specimens from Ecuador is comparatively much 

 shorter. Since the skin of the male has been completely 

 softened its tail proves to be only 27,7 % of the length of 

 head and body. In the adult female, which has been care- 

 fully mounted, the relation between the tail and the head 

 and body is practically quite the same or 27,5 %. The cor- 

 responding percentages for the young specimens are to judge 

 from the skins also similar. From this will be apparent that 

 the Dinomys of Ecuador has a comparatively shorter tail 

 than as well the type specimen from Peru as those from the 

 eastern slopes of the Andes. Although this difference is not 

 great I think it must be considered to indicate a certain 

 racial difference. This feature is well visible on the accom- 

 panying figure (p. 51). 



The dimensions of the skull of the old female Z){- 

 nomys are as follows: 



? old. 



Total length of skull 134,5 mm 



Basal length to gnathion 123 » 



Zygomatic breadth 79,5 » 



Interorbital breadth 39,5 39,5 » 



Breadth of palate between premolars 4 « 



» » » > m^ ... 15 > 



Length of nasals 44,5 » 



» » frontals 48,5 » 



» » maxillary tooth series . . . 35,5 » 



» » molars only 26 » 



These cranial dimensions agree so closely as well with 

 those which Peters has recorded^ for the type as with those 

 communicated by Preller^ for Goeldi's old specimen that 

 no racial difference can be based on the same. Nevertheless 

 I think that the already mentioned shortness of the tail of 

 all 4 specimens from Ecuador prohibits an Identification with 

 the typical Dinomys hranicki from the eastern side of the 



1 Festschr. z. F. 100 jähr. Ges. Naturforsch. Fr. Berlin 1873. 

 ' Arch. f. Naturgesch. Jahrg. 73. Berlin 1907. 



