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lodon and Megatherium, there not being a rudiment of the first toe, or even of 

 its cuneiform bone in either of these extinct genera. In the Mylodon we have 

 seen that the second toe, though small, is complete, and supports a claw : in 

 the Megatherium the second toe is unquestionably represented by its cuneiform 

 bone, or if the metatarsal be blended therewith the traces of the original separation 

 have disappeared. This bone, in the collection presented to the College by Sir 

 Woodbine Parish, is compressed and of an irregularly semicircular form : its 

 proximal margin or base is occupied by the long, narrow, undulating surface 

 adapted to that on the os naviculare. On the outer side, near the upper end of 

 the base, there is a flat, subcircular articular surface, which has been applied to 

 a corresponding surface on the metatarsal of the third toe : there is no other ar- 

 ticulation, but the distal convex margin is as rough as the rest of the non-arti- 

 cular surface of the bone. 



All the existing Edentata, except the Sloths, have the toes of the hind-foot 

 of the normal structure and number. The Chlamyphorus not only differs from 

 the Mylodon in the distal confluence of the tibia and fibula, but also in the nor- 

 mal mode of the articulation of these bones with the astragalus, which conse- 

 quently has the same essential form as in the Glyptodon and recent Armadillos. 

 The foot, as a corollary to this structure of the ankle-joint, is planted firmly on 

 the ground by its flat surface, not by its outer margin. The proportions of the 

 toes are the reverse of those in the Mylodon and Megatherium : the middle me- 

 tatarsal is the longest ; the second is also longer than the two outer ones ; and 

 the innermost or first toe is not only present in the Chlamyphore, but is longer 

 than the outermost toe. All the five toes are armed with claws ; and strange 

 and anomalous as the two-toed or three-toed feet of the Sloths may at first sight 

 appear, they have more real correspondence, in the structure of the tarsus and 

 the proportions of the digital bones, with the feet of the Mylodon and Megathe- 

 rium, than have those of any of the Armadillo tribe. The Glyptodon agrees 

 with the Chlamyphorus in the pentadactyle structure of the hind-foot, the os 

 naviculare having three facets for as many cuneiform bones, the innermost of 

 which supports a metatarsal bone and two phalanges, which is the ordinary 

 structure of the hallux. 



In both species of Sloth the hallux or first toe is abortive and represented 

 by a single small compressed bone, consisting apparently of the confluent cunei- 

 form and metatarsal, with probably a sesamoid, which may form the posterior 



