xni 



PHYLUM CHORDATA 



511 



consisting of two long and slender horizontal rami, with a very 

 short symphysis. 



In the Sloths (Fig. 1152) the cranial region is elevated and rounded, 

 the facial short ; the frontal region is elevated, owing to the develop- 

 ment of extensive frontal air-sinuses. The premaxillse are small, 



par 



nas 



eaz.oc 



FIG. 1149. Skull of Armadillo (Dasypus sexcinctus). Letters as in Figs. 1144 1146. In 

 addition, peri, periotic. 



and not firmly connected with the maxilla, so that they are com- 

 monly lost in the macerated skull. The jugal (ju.) develops a 

 strong zygomatic process which bifurcates behind into two branches, 

 neither of which is connected with the rudimentary zygomatic 

 process of the squamosal, so that the zygomatic arch remains in- 

 complete. There are, at most, the rudiments of post-orbital pro- 



par 



occ.cond 



FIG. 1150. Skull of Ant-eater (Myrmecophaga), lateral view, al.sph. alisphenoid ; cond. 

 condyle of mandible ; cor. coronoid process of mandible ; ex.oc. ex-occipital ; ext. and. 

 external auditory meatus ; fr. frontal ; ju. jugal ; Icr. lacrymal ; max. maxilla ; nas. nasal ; 

 occ. cond. occipital condyle ; pal. palatine ; par. parietal ; p.mdx. pre-maxilla ; s.oc. supra- 

 occipital ; sq. squamosal ; ty. tympanic. 



cesses of the f rentals. The pterygoids develop vertical laminae 

 and form no palatine plates. The ascending ramus and coronoid 

 process of the mandible are both well developed. 



In the American Ant-eaters and Armadillos the bones of the 

 fore-limb are short and powerful. The scapula in the Ant-eaters 



i i 2 



