CH. XVI.] 



GENERAL CHARACTERS. 



281 



condition in some of the lower vertebrates. 1 Fig. 90 repre- 

 sents the manus in one of its most complete, and at the 

 same time most generalised, forms, as seen in one of the 

 Water Tortoises (Chelydra serpentined). 



The carpus consists of two principal rows of bones, an 

 upper or proximal row, containing three bones, to which 

 Gegenbaur has applied the terms radiak (r), intermedium (/), 



FIG. 90. Dorsal surface of the right manus of a Water Tortoise (Chelydra ser- 

 fentzna), after Gegenbaur. u ulna ; R radius ; u ulnare ; i intermedium ; r radiale ; 

 c centrale ; i 5 the five bones of the distal row of the carpus ; nfl- m 5 the five 

 metacarpals. 



and ulnare (u\ the first being on the radial or preaxial side 

 of the limb. The lower, or distal row, contains five bones, 

 called carpale i, 2, 3, 4, and 5 respectively, commencing on 

 the radial side. Between these two rows, in the middle of 

 the carpus, is a single bone, the centrale (c). 



In this very symmetrical carpus, it will be observed that 



1 See Gegenbaur, " Untersuchungen zur vergleichenden Anatomic." 

 Ites Heft, Carpus und Tarsus. 1864. 



