TEETH OF ARMADILLOS I 73 



complete the arcade. Tlie premaxillaries are veTj small, r.nd are 

 usually lost in dried skulls. Coupled with these points of likeness 

 are some differences. The lower jaw, for instance, has a well- 

 marked coronoid process. The pterygoids do not meet in the 

 middle line. The teeth are five or four in each half of each jaw. 

 There is no trace of a second set. 



A peculiarity of the Sloths is the enormous number of dorsal 

 vertebrae. There are twenty-three of these in Choloejins hoffmanni, 

 but only fifteen to seventeen in the Three-toed Sloth, Bradyp'us. 

 As in other American Edentates, the acromion joins the coracoid. 

 This connexion occurs in both the Two-toed and the Three-toed 

 species. The limbs of these creatures are very long, a concomitant 

 of an arboreal life. The femiu: has no third trochanter. The 

 genus Brad 1/ jilts, which Ijy reason of the fact that it has not lost 

 the third toe on the manus seems to be more primitive than 

 CJioh)cj)iis, shows another structural feature which does not bear 

 out this conclusion. The trapezoid and the os magnum of the carpus 

 are united, while in CJwloejms they are perfectly distinct bones. 



The intestine has no caecum. 



There are several species of Sloths. Eminently perfect though 

 the organisation of the Sloth in relation to its particular sur- 

 roundings appears to us, Buffon selected the animal as the very 

 type of imperfection in nature. " One more defect," he wrote, 

 " they could not have existed." 



Fam. 3. Dasypodidae. — The family Dasypodidae or Arma- 

 dillos contains a considerable number of genera. Tatusia, Toly- 

 peutes, Dasypus, Xenurus, Priodon} and Cldamydopliorus. They 

 have all a more or less rigid covering of bony plates imbedded in 

 the skin, which are not in the least comparable with the scales of 

 the Manis. Save the Whales, in one or two genera of which 

 traces of a dermal armature exist, the Armadillos are unic[ue 

 among existing mammals in this particular. The term " Edentate " 

 is especially inapplicable to the Armadillos; the genus Friodon 

 may have more than forty teeth in each jaw ; a total of ninety 

 was found in one specimen examined by Professor Kiikenthal. 

 In the tendency of the teeth to multiply, we have another 

 example of a state of affairs which characterises so many "Whales. 

 Generally, however, seven to nine is the number of teeth in each 



^ This name is written " Prionodos " by Gray, which might lead to a confusion 

 with the Carnivore Prionodon. 



