48 



EDENTATA. 



Creator display itself more fully than in the 

 construction of these contemned and apparently 

 apathetic beings. I must refer the reader to 

 a highly interesting paper by Professor Buck- 

 land in the Linnaean Transactions, in which 

 the libels of Cuvier on this maligned animal 

 are beautifully and satisfactorily refuted. 



The Ant-eaters and Armadillos, on the other 

 hand, which may be considered as the true 

 Edentata, are constructed for very different 

 habits, and the Chlarnyphorus must be consi- 

 dered as offering a very near affinity to the 

 latter genus. The Ant-eaters with their thick 

 long hair and fossorial claws, and the long ex- 

 tensile tongue with which they are furnished, 

 are thus enabled to scratch or dig up the ant- 

 hills and to receive their minute but multi- 

 tudinous inhabitants on the mucous surface of 

 the tongue ; whilst by their long dense hair 

 they are protected from the annoyance or dan- 

 ger which their little troublesome victims 

 would otherwise inflict. The Armadillos and 

 the Chlamypkorus, on the other hand, pursue 

 their insect prey either on or beneath the sur- 

 face of the earth, and are protected from the 

 attacks of their enemies by the panoply of 

 mail with which they are furnished. 



The osseous system. The cranium. The ge- 

 neral character which at once strikes us in look- 

 ing at the cranium of the Sloths (Jig. 29) is its 



Fig. 29. 



Orycteropus the two parietals are united from 

 an early period ; in the Ant-eaters, on the con- 

 trary, they remain separate. In the Sloth the 

 squamous portion of the temporal bone is of 

 large dimensions, and the acoustic portion of 

 but moderate size. The zygomatic process is 

 small and does not reach the jugal bone ; a con- 

 struction which is still more conspicuously 

 seen in the Ant-eaters. The occipital bone is 

 large ; the squamous portion broad and 

 rounded, the superior part being continued to 

 the inferior by an obtuse angle in the Sloths, 

 and by nearly a right anglein the true Edentata. 

 The occipital foramen is round. The jugal 

 bone offers some remarkable peculiarities in its 

 form. In the Ant-eaters (fig. 31) it occurs in a 



Fig. 31. 



Head of the Ant-eater. 



very imperfect condition, being merely an ob- 

 long plate of bone, terminating posteriorly in 

 a rounded point, situated in the posterior ex- 

 tremity of the superior maxillary bone, and 

 beneath the lachrymal, extending posteriorly 

 scarcely beyond the latter ; consequently it is 

 remote from the temporal bone throughout the 

 whole length of the temporal fossa, and there 

 is no zygomatic arch. In the Manis (Jig. 

 32) it is absolutely wanting. In the Arma- 



Fig. 32. 



Head of the Sloth. 



extreme shortness, particularly with regard to 

 the facial portion, and the roundness of its 

 whole contour. In the insectivorous forms 

 the muzzle, on the contrary, is greatly elongated. 

 TheJ'rontal bone in the Tardigrada is large, and 

 the anterior portion convex ; it has no zygo- 

 matic process, and the frontal and orbital por- 

 tions pass into each other by a very obtuse 

 angle. The parietal bone in most is of a square 

 figure. In the Armadillos (Jig- 30) and in the 



Fig. 30. 



Head of the Armadillo. 



dillos it is somewhat more fully developed; 

 it is larger and higher and reaches the tem- 

 poral bone by its posterior portion. In the 

 bloths, especially in the Bradypus didactylus, 

 or Unau, it attains a much greater size, and has 

 on its inferior margin a long process extending 

 downwards and backwards almost to the base 

 of the lower jaw. This remarkable process is 

 also found in the enormous fossil animal the 

 Megatherium (Jig. 33). The posterior extremity 

 of the jugal bone is remote from the zygomatic 

 process of the temporal in the Sloths, but in the 

 Megatherium these bones are united, and the 

 zygomatic arch is therefore complete. The in- 

 ferior maxillary bone varies excessively in this 

 order. In the Orycteropus, Manis, and Myrme- 

 cophaga, it is extremely long and depressed ; 

 its height does not greatly vary in the whole of 

 its length. In the Armadillos it is much shorter, 

 and in the Sloths it is extremely short and trun- 

 cated. The intermaxillary bone is excessively 

 small in the Ant-eaters and the Sloth, which are 

 not furnished with any incisive teeth, but in 

 Armadillos it attains a somewhat greater degree 

 of development, especially in the genus Da- 



