2 22 PHYLUM CHORDATA 



dorsal to the latter. In addition to these are a number of bones 

 which join the fin with the cranium. 



Exercise 30. Draw the pectoral fin and girdle. 



The Ventral, or Pelvic, Fins. Each of these consists of about 

 five radials. At their proximal ends they articulate with a large 

 plate which represents the fused basals. These two plates lie 

 alongside of each other in the median area ; no pelvic girdle is 

 present. 



Exercise 31. Draw the pelvic fins. 



