OSTEOLOGY AND ARTHROLOGY 49 



is styloid in form. As to the other two fingers, they are 

 placed, one in front and the other behind ; the first, which 

 articulates with the short metacarpal, fused at its upper 

 end with the principal bone of the metacarpus, in position 

 represents the thumb. The other, which is the third 

 finger, articulates with the inferior extremity of the thinnest 

 bone of the metacarpus ; it is sometimes closely united 

 to the corresponding border of the first phalanx of the large 

 - — that is to say, of the median — digit. 



The Anterior Limbs in Certain Animals 



Plantigrades : Bear (Fig. 33). — The scapula of the bear 

 approaches in shape to a trapezium, of which the angles 

 have been rounded off. The anterior border (cervical) is 

 strongly convex in the part next the glenoid cavity. The 

 junction of the superior (spinal) and the cervical border 

 forms almost a right angle, the summit of which corre- 

 sponds to the origin of the spine. At its posterior angle 

 there is a prominence, directed downwards, the surface of 

 which is hollowed and is separated from the infraspinous 

 fossa by a crest, so that at this level a third fossa is added to 

 the infraspinous one. The neck of the scapula is but slightly 

 marked. The acromion is prominent, and projects a little 

 beyond the glenoid cavity. 



The clavicle is rudimentary, but, as an example of the 

 complete development of this bone in plantigrade quadru- 

 peds, we may cite the marmoset. 



The humerus is furnished at its superior extremity with a 

 large tuberosity, wide, and situated in front of the head of 

 the bone ; the effect of this is that the bicipital groove is 

 internal. As in man, the great tuberosity does not reach so 

 high as the humeral head, but it approaches more nearly 

 to that level. The deltoid impression is very extensive, 

 and descends pretty far down on the body of the bone. The 

 epitrochlea is prominent ; the epicondyle is surmounted by 

 a well-marked crest, curved and flexuous in outline. 



The articular surface, which is in contact with the 

 radius, is not a regularly formed condyle ; it is a little 



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