530 



ZOOLOGY 



SECT. 



Tlie j)dvis of the American Anteaters is elongated, with a short 

 symphysis pubis. The ischia unite with the spinal column. There 

 is no third trochanter. The tibia and fibula are nearly straight, 



Fic. 1143. — Shuuldor-tdi-dle of Three-toed 



SlOtb (l>rad>/jms tridactylus). nr,-. acin- 

 inioii ; cl. clavicle ; cor. coracoid. 



Vu:. 1144.— RightmanusofThree-toed Sloth. 



fun. cuneiform; Ivn. lunar; uu^. tirst uiuta- 

 carpal ; mc^. rudiment of fifth metacarpal ; 

 ins. pisiform ; r<id. radius ; sc. scaphoid ; tnl. m. 

 trapezoid and magnvun united ; v.in. ulna ; line. 

 unciform. 



and parallel with one another. In Cydoturus the pes is modified 

 to form a climbing organ. 



In the Sloths the pelvis is short and wide; the spines of the 

 ischia unite with the anterior caudal vertebrre so that sacro- 



sciatic foramina are formed as 

 in Anteaters. The femur is 

 loDg and slender; it is devoid 

 of third trochanter. The tibia 

 and fibula are also long and 

 slender. At its distal end 

 (Fig. 1145) the fibula develops 

 a peg-like process (x) which 

 fits into a depression in the 

 outer face of the astragalus. 

 The calcaneal process is ex- 

 tremely prolonged in Braclypus, 

 in which there is a tendency 

 to ankylosis between the tar- 

 sal bones, and the proximal 

 phalanges ankylose with the 

 metatarsals. 



In the Armadillos the pelvis 

 (Fig. 114 6) is extremely long, 

 and both ilia and ischia are 

 firmly fus'>d with the spinal column. The femur has a pro- 

 minent third trochanter. The bones of the pes (Fig. 1147) are 

 normal. 



a? 



caLc 



cbcl 

 metut.s 



TTtetal. i 



Fig. 1145.— Pe.s of Three-toed Sloth. " ^ 

 astragalus ; c<t\c. calcaneum : c'"/. cuboid ; 

 //(. fibula ; riuioc. mesocuneiform ; metat^. 

 vestige of first metatarsal ; tnetaVK vestige 

 of fifth metatarsal ; nav. navicular ; tib. 

 tibia ; .»;, peg-like process at distal end of 

 fibula. 



