XIII.J THE FKOG. 217 



the other on the astragalar side, articulate. 

 The latter is connected by ligamentous fibres, 

 within which a nodule of cartilage may be 

 found, with the first and second metatarsals, 

 and supports the calcar (d. f). 



d. The digits. Five in number; the internal one 

 the shortest, the fourth the longest. Their com- 

 position — 



a. The first, or hallux (the most internal) ; a 

 metatarsal bone, followed by two phalanges. 



/3. The second : same as a, but longer. 



7. The third : a metatarsal bone with three pha- 

 langes. 



S. The fourth: a metatarsal bone and four 

 phalanges. 



e. The fifth : like the third, but a little shorter. 



f On the anterior or tibial edge of the foot there 

 are two, small, more or less cartilaginous, ossicles, 

 articulated with the tarsus (c. ff) in such a 

 manner as to resemble an extra digit. This 

 calcar, or spur, supports the horny prominence 

 referred to above. 



E. Dissection of the ekog's hind-limb to illustrate 



ITS MYOLOGY. 



(For the following dissection it is desirable to have a frog 

 wMch has been lying some time in. spirit.) % 



1, Lay the animal on its back, and make an incision 

 through the skin on the front of the limb from the 

 symphysis pubis to the ankle ; then reflect the skin 



