LÖNNBERG, OCCURRENCE OF FIRST HIND TOE IN THE FOX. 3 



ning process, but on the right hind foot fortunately the 

 basal phalanx as well remains fixed to the skin as fig. 2 

 proves. This basal phalanx is also well developed and does 

 not give the impression of a rudimentary organ. The length 

 of the claw is fully 8 mm. measured in a straight line, and 

 its height at the base is 4 Va mm. The basal phalanx is 

 about 4 V:' ram. in length. Its proximal articulating surface 

 measures about 5 mm. in height. The transverse diameter 

 of the bone proximally, where it is thickest, is 3,4 mm. The 

 fact that there is a proximal articulating surface proves that 

 there has been a metatarsal bone against which it articulated 

 in life-timo. The general shape and the fact that the claw 

 is worn indicates also that this first toe has been firmly 

 attached to the foot and probably connected with muscles. 



Fig. 2. First hind toe of the right side showing claw, basal phalanx and 

 proximal articulating surface of the latter. f. 



The primitive Carnivora had 5 toes as well on the hind 

 as on the före legs. These toes were originally of about the 

 same approximate length as they still are in the Bears. 

 When the Canidoe became more and more specialised as 

 swift runners, and in connection with this became digitigrad, 

 the first hind toe no longer was useful, but superfluous and 

 perhaps even obnoxious. Its elements, especially the meta- 

 tarsal, were shortened so that it was lifted up above the 

 ground. — It is this stage which is reproduced by the fox 

 from Biskops-Arnö. — During the development and further 

 specialisation of the CanidcE the reduction of the first hind 

 toe continued until it finally disappeared from view exter- 

 nally, and its only remaining part was the slight rudiment 

 of the proximal portion of the first metatarsal as mentioned 

 above. 



As has already been hinted above some domestic races 

 of dögs are provided with »spurs», viz. rudiments of a first 



