ARKIV FÖR ZOOLOGI. BAND 12. NIO 13. 



Measurements in % of the distance 



between the sphenoid suture and the 



gnathiorx 



Ps. lycoides Ps. magellanicua 



o/ 



/o 







o/ 



/o 



Distance between postorbital processes 



Postorbital constriction 



Breadth of braincase 



Length of palate 



Breadth across posterior end of p* . . 



V 



Front of canine to back of w^ . . . 



Outer length oi p* 



Length of w^ 



Breadth » » 



Length » m^ 



Breadth » » 



Length of m^ 



Length of mandible 



31,8^ 



20,1 



38,0 



72,5 



38,5 



33,8 



18,5 



62,1 



12,6 



8,0 



11,7 



5,4 



8,4 



13,0 



6,6 



3,4 



110,7 



34,2 

 22,0 

 40,3 

 72,7 

 40,6 

 35,2 

 20,1 

 64,4 

 13,3 



8,2 

 12,2 



5,7 



9,1 

 13,2 



7,3 



3,7 

 112,3 



34,1 

 23,8 



45,3 



73,6 



40,7 



36,0 



19,0 



66,9 



14,1 



8,5 



13,4 



5,7 



9,5 



14,4 



7,0 



3,5 



110,4 



45,5 

 73,2 



13,3 



8,9 

 12,4 



4,9 



14,2 



7,1 



2,6(?) 



^ The postorbital process is not quite normal on one side. 



In some instances there is a small difference conspicuous 

 with regard to the relative dimensions of the two species, 

 and then the lycoides skulls make the impression of repre- 

 senting a stage which corresponds to such a one as appears 

 somewhat låter ontogenetically during the development of 

 similar skulls. Instances of this are among others the fol- 

 lowing. The interorbital breadth appears to be a little larger 

 in lycoides than in magellanicus, just as the forehead increases 

 in width ontogenetically. On the other hand the postorbital 

 constriction is narrower in lycoides (and even narrower in 

 the larger and older specimen of this form) than in magel- 



