i 5 8 



SELA CHI1 



Tribe 2. 



The pectoral fins fuse in front with the sides of the head, and 

 the branchial openings are quite ventral. The rostrum, as a 



Fig. 121. 



Skeleton of Raja batis, L. (From Owen, Anal, of Vertebrates, by permission of Messrs. Long- 

 mans and Co.) 7, scapular region of pectoral girdle; 8, '.', 10, segments of anterior u\N of 

 pectoral fin ; 11, posterior axis ; 12, radials of expanded pectoral fin; 19, preorbital process; 

 52, cartilage plate joining scapula to vertebra] column; 55, posterior outgrowth oi pectoral 

 girdle; G?>, pelvic girdle ; 68, basipterygium ; c, anterior enlarged radial ; v, pelvic-tin radials. 



rule, is much developed. In this division most of the changes in 

 the skeleton described above (p. 154) are carried out. Extra- 

 branchials arc preserved in the Rhinobatidae and in Tryg&n. The 

 iliac process may be much developed ; since it is large in the 

 Holocephali and in the Tetrapoda, this is possibly a primitive 

 character. 



