52 THE BONES AND JOINTS. 



piece (h), and a flattened beak-like piece (//). Duges considers 

 these pieces as the first and second ossa cuneiformia ; I rather incline 

 to Meckel's opinion that they represent a rudimentary hallux, the 

 first being the os metatarsi, the second a phalanx. Both are com- 

 posed of calcified cartilage ; in B. temporaria the lime-deposit seems 

 to be less than in R. oxyrkinns and R. esculenta, and the projection 

 consequently softer *. 



b. The metatarsal bones, ossa metatarsi (Fig. 47, m 1V\ The 

 five ossa metatarsi are long, thin tubular bones, the anterior articular 

 extremities of which are broader above and narrow below, hence are 

 wedge-shaped, and anteriorly present flat surfaces for articulation 

 with the tarsiis. The shafts are long and thin ; the posterior 

 extremities have rounded heads. The comparative length of these 

 is as follows : the fourth is the longest, then come the third, fifth, 

 second, and first in order. In structure they resemble other tubular 

 bones. 



c. The phalanges, phalanges diyitomm (Fig. 47). The total lengths 

 of the separate toes correspond with that of the ossa metatarsi, but 

 the distinctive differences are increased, partly by the difference in 

 number and partly by the varying lengths of the phalanges. The 

 first and second toes have each only two phalanges, the third and 

 fifth have each three, the fourth, which is the longest, has four. 

 The terminal phalanges are somewhat hooked towards the plantar 

 surface. 



1 In the text these two cartilages are termed the ' supplemental toe.' 



