ORDER BATRACHIA. 453 



two cartilaginous pieces in the horned toad ; in the other 

 species it is terminated by a disc, which serves for the inser- 

 tion of the muscles. 



The bones of the furca and clavicles are entirely joined, 

 on one side with the sternum, and on the other with the sca- 

 pula ; ^at their point of junction, those three pieces have 

 a wide oval aperture between them, which communicates by 

 a short canal into the scapulo-humeral articulation ; this 

 peculiarity is very evident in the horned toad. It is not 

 met in most of the others. 



The omoplate is formed of two articulated pieces, the 

 upper one of which looks towards the spine. 



The bones of the fore-arm are synostosized, so as to form 

 but a single one, hollowed on each side and underneath, with 

 a furrow of no great depth. 



The carpus is generally composed of eight bones ; the 

 metacarpus of four ; the front toes are four in number ; there 

 is only a vestige of a thumb supported by a metacarpal bone. 



The femur is straight and without trochanters ; after it, 

 comes the piece erroneously supposed to represent the two 

 bones of the leg, which we have noticed before. The real 

 tibia and fibula which most authors have represented as 

 the astragalus and calcaneum, are separated in their whole 

 length. 



The tarsus has four, the metatarsus five bones. 



The myology of the toad exhibits in its examination the 

 same irritability, strength, and sensibility to galvanic action 

 in the muscles, as we find in the frog. It is unnecessary 

 here to describe these muscles in detail, as enough has been 

 said on this subject in treating of the frog. 



Though the nerves in the toad are very distinct and large, 

 the cavity of the cranium where they originate is small. 

 The brain itself is of very small volume. 



The hemispheres are smooth, without circumvolution, 



