lis FORE-LIMB OF THE CROCODILE. 



fishes, then the same conclusion must apply to the same 

 arch in other animals, np to man himself. 



The anterior locomotive extremity is the diverging ap- 

 pendage of the arch, under one of its numerous modes 

 and grades of development. The proximal element of 

 this appendage, or that nearest the arch, is called the 

 "humerus," 53 (Fig. 18). The second segment of the 

 limb consists of two bones ; the larger one, 54, is called 

 the " ulna :" it articulates with the outer condyle of the 

 humerus by an oval facet, the thick convex border of 

 which swells a little out behind, and forms a kind of 

 rudimental " olecranon ;" the distal end is much less than 

 the proximal one, and is most produced at the radial side. 



The radius, 55, has an oval head; its shaft is cylin- 

 drical ; its distal end oblong and subcompressed. 



The small bones, 56, which intervene between these 

 and the row of five longer bones, are called "carpals;" 

 they are four in number in the crocodilia. One seems to 

 be a continuation of the radius, another of the ulna ; these 

 two are the principal carpals ; they are compressed in the 

 middle, and expanded at their two extremities : that on 

 the radial side of the wrist is the largest. A third small 

 ossicle projects slightly backwards from the proximal end 

 of the ulnar metacarpal; it answers to the bone "pisi- 

 forme" in the human wrist. The fourth ossicle is inter- 

 posed between the ulnar carpal and the metacarpals of 

 the three ulnar digits. 



These five terminal -jointed ra3^s of the appendage are 

 counted from the radial to the ulnar side, and have re- 

 ceived special names ; the first is called " pollex," the 

 second "index," the third "medius," the fourth "annu- 

 laris," and the fifth " minimus." The first joint of each 

 digit is called " metacarpal ;" the others are termed " pha- 



