THE- EDENTATES 171 



Edentates still remaining, namely the Old-World members of 

 the order. 



The skull of the Pangolin recalls at once the general features 

 of the skull of the American Anteater. This curious scaly 

 Oriental Mammal, also an Anteater in habit, is nevertheless 

 widely removed from the American form and the relationship 

 of the two animals is very distant if indeed it exists at all. 

 No teeth are present although vestiges have been found. The 

 features consequent upon absence of teeth occur in the Pangolin 

 as well as in the American Anteater. Thus is presented a case 

 of parallel evolution of which the stimulating factor is known. 

 It is the absence of teeth which has brought about the appar- 

 ent similarity of the two forms. 



It is probable that the Aard-vark (Fig. 57) was originally 

 derived from a mammalian stock possessing the typical placen- 

 tal dental formula: 



if,c{,pi,Mf. 



but the number of cheek teeth has increased during evolution to 

 - although the anterior members of the series like the in- 

 cisors and canines are quickly lost. The effect of absence of 

 teeth upon the anterior part of the maxilla and mandible is 

 clearly seen. The cheek teeth have the form of double columns 

 lacking enamel and similar in all general respects to the teeth 

 of the American Edentates but differing in their histological 

 pattern. The milk teeth are brachyodont and each possesses 

 two roots. This curious African Anteater possesses a brain 

 which Elliot Smith states is "distinctly comparable with a 

 primitive Ungulate type" and although there may be some dis- 

 tant relationship, as yet unproven in entirety, with the Ameri- 

 can Edentates, this speculation is all that we can offer at pres- 

 ent regarding its ancestry. 



