410 



ANATOMY OF VERTEBRATES. 



inner aide of the entocuneiform and scaphoid. The ungual phalanx 

 of the hallux is simple ; those of the three middle toes are cleft 

 at the apex. 



In the Myrmecoi)Uacja, fig. 263, the scapula, 5i, is very broad, 

 with a sub-circular contour, and is traversed by two spines, the 

 upper one prolonged as an ' acromion ' tow^ard the coracoid, and 

 supporting a small cLavicular bone {Myrm. juhata) or joined to a 

 complete cla\TLcle {Myrm. didactyla). The humerus, 53, is greatly 

 expanded at its distal end, especially by the entocondyloid crest, 

 which is recurved and perforated. The radius, 54, and ulna are 

 of nearly equal length, the acromion, 55, has the lower angle pro- 

 duced. The carpus consists of the usual eight bones, fig. 278, 

 viz. scaphoides s, lunare /, cuneiforme c, pisiforme p, which is 



278 



Bones of the hand, Myrmecopha{jajubata. cli. 



produced like a carpal calcaneum. The trapezium, t, supports a 

 slender pollex, i ; the trapezoides, z, a longer and larger index, ii ; 

 the strong, four-sided, outwardly-ridged metacarpal of the medius, 

 III, rests its base upon the magnum, m, and unciforme, u ; and is 

 wedged between that of the index, ii, and annularis, iv. The 

 minimus, v, which is articulated more to the annularis than to the 

 unciforme, 7i, has but two phalanges, and is clawless. The ungual 

 phalanges are dorsally grooved, not notched. In the Myrmecophaga 

 didactyla the metacarpal rudiments of the pollex and minimus 

 are liidden beneath the shin : the annularis metacarpal supports 

 a clawless phalanx : the two conspicuous digits are the index and 

 medius, the latter the largest. The femur, fig. 263, 65, has a crest 

 along its outer margin : the tibia and fibula, 67, are distinct : the 

 foot is i)lantigrade and pentadactyle, with a calcaneum long and 

 compressed in the great terrestrial species, but short in the 



