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vexities of the adjoining phalanx, and the median ridge fitting the median canal 

 of the same, are so deep as to prevent any lateral motion, and give great strength 

 to the joint. The upper production of the basal articulation of the ungual pha- 

 lanx is flattened vertically, and rough, serving probably for the implantation of 

 the extensor tendon. The osseous sheath of the claw is continued forwards 

 from the upper and lateral margins of the articular cavity, and from those of the 

 flat rough oval surface at the proximal half of the base of the claw. The"osseous 

 sheath, which varies from half a line to one line and a half in thickness, appears 

 to have extended forwards over at least the basal third of the long process sup- 

 porting the claw ; but it is broken away more or less in both the feet. The 

 claw-process, which forms the chief part of the ungual phalanx, is conical, 

 slightly deflected, and inclined inwards ; convex above and at the sides, which 

 are divided from the under surface by sharp edges : the under surface, owing 

 to the oblique line from which the sides of the ungual sheath arise, is less than 

 half the length of the upper surface ; it is convex transversely along its middle 

 part, concave on each side ; these lateral channels are bounded externally by the 

 sharp edges above-mentioned, and deepen as they approach the base of the pha- 

 lanx. The vessels and nerves which supplied the secreting organ of the enormous 

 claw were lodged in the above channels : of the two large oval perforations in 

 the lower rough tract, the external one leads directly to the beginning of the 

 corresponding channel ; the internal one conducts to the cancellous structure of 

 the phalanx. The claw-process for the extent of one inch and a half from its 

 apex is impressed above with a shallow longitudinal channel. 



The ungual phalanges of both the claw-bearing toes of the hind-foot resemble 

 those of the fore-foot in the perforated and grooved character of their outer 

 surface. 



The two outer metatarsal bones are the only ones the size and strength of which 

 are proportionate to that of the principal bones of the tarsus, as the calcaneum 

 and astragalus. That which supports the fourth toe (?»4), counting as if the normal 

 number had existed on the inner side of the foot, presents a short trihedral body, 

 expanding into two extremities. The proximal end is obUquely truncated on the 

 tibial or inner side, with the lower angle produced downwards. A smooth articular 

 surface, slightly concave vertically, and slightly convex transversely, occupies 

 this oblique base, and is divided by a moderate constriction into an anterior 

 smaller ovate surface, adapted to the outer basal process of the middle meta- 



