266 THE VERTEBRATE SKELETON. 



centrale and the bone representing carpalia 3, 4 and 5 ; this 

 cartilaginous patch represents carpalia 1 and 2 (fig. 48, A, 7). 

 The bone representing carpalia 3, 4 and 5 is a good deal 

 larger, rounded, and well -ossified ; it articulates with the 

 ulnare, the pisiform, and the third, fourth, and fifth meta- 

 carpals. 



The hand. Each of the five digits consists of an elongated 

 metacarpal, terminated at each end by an epiphysis, and of a 

 varying number of phalanges. The terminal phalanx of each 

 digit has an epiphysis only at its proximal end, the others have 

 them at both ends. 



The first digit, or pollex, is the stoutest, and has two 

 phalanges, the second has three, the third four, the fourth 

 three, and the fifth two. The terminal phalanx of each of the 

 first three digits is pointed and sheathed in a horny claw ; and 

 is also marked by a pair of prominent lateral grooves. 



THE PELVIC GIRDLE. 



The pelvic girdle of the Crocodile consists of four parts, a 

 dorsal element, the ilium, an anterior ventral element, the 

 pubis, a posterior ventral element, the ischium, and an 

 accessory anterior ventral element, the epipubis. All except 

 the epipubis take part in the formation of the acetabulum, 

 which is perforated by a prominent hole. 



The ilium (fig. 49, 1) is a thick strong bone, firmly united 

 on its inner side with the two sacral ribs. Its dorsal border 

 is rounded, its ventral border bears posteriorly two irregular 

 surfaces, completed by epiphyses, which are united respectively 

 with the ischium and pubis. 



The ischium (fig. 49, 2) the largest bone of the pelvis, 

 is somewhat contracted in the middle and expanded at either 

 end. Its proximal end, which is formed by an epiphysis, 

 bears two surfaces, one of which is united to the ilium, 

 while the other forms part of the acetabulum. The anterior 

 border is also drawn out dorsally into a strong process, which 



