thoracic in the 

 human body : 

 they extend 

 from the head 

 to the com- 

 mencement of 

 the tail, and 

 are at once re- 

 cognizable by 

 the nature of 

 the elements 

 which enter in- 

 to their com- 

 position ; each 

 vertebra being 

 provided with 

 a superior arch 

 (fig. 219, b), 

 through which 

 passes the spi- 

 nal cord, a su- 

 perior spinous 

 process (c), 

 and two trans- 

 verse processes 

 (d), to the ex- 

 tremities of 

 which the ribs 

 are generally 

 attached. The 

 caudal verte- 

 brae are com- 

 posed, as we 

 have already 

 seen, of differ- 

 ent elements: 

 the transverse 

 processes ei- 

 ther do not 

 exist, or are 

 very feebly de- 



PISOES FISHES. 



Fff.221. 



491 



